2 # For a description of the syntax of this configuration file,
3 # see extra/config/Kconfig-language.txt
6 mainmenu "uClibc C Library Configuration"
8 config DESIRED_TARGET_ARCH
13 prompt "Target Architecture"
14 default TARGET_alpha if DESIRED_TARGET_ARCH = "alpha"
15 default TARGET_arm if DESIRED_TARGET_ARCH = "arm"
16 default TARGET_avr32 if DESIRED_TARGET_ARCH = "avr32"
17 default TARGET_bfin if DESIRED_TARGET_ARCH = "bfin"
18 default TARGET_cris if DESIRED_TARGET_ARCH = "cris"
19 default TARGET_e1 if DESIRED_TARGET_ARCH = "e1"
20 default TARGET_frv if DESIRED_TARGET_ARCH = "frv"
21 default TARGET_h8300 if DESIRED_TARGET_ARCH = "h8300"
22 default TARGET_hppa if DESIRED_TARGET_ARCH = "hppa"
23 default TARGET_i386 if DESIRED_TARGET_ARCH = "i386"
24 default TARGET_i960 if DESIRED_TARGET_ARCH = "i960"
25 default TARGET_ia64 if DESIRED_TARGET_ARCH = "ia64"
26 default TARGET_m68k if DESIRED_TARGET_ARCH = "m68k"
27 default TARGET_microblaze if DESIRED_TARGET_ARCH = "microblaze"
28 default TARGET_mips if DESIRED_TARGET_ARCH = "mips"
29 default TARGET_nios if DESIRED_TARGET_ARCH = "nios"
30 default TARGET_nios2 if DESIRED_TARGET_ARCH = "nios2"
31 default TARGET_powerpc if DESIRED_TARGET_ARCH = "powerpc"
32 default TARGET_sh if DESIRED_TARGET_ARCH = "sh"
33 default TARGET_sh64 if DESIRED_TARGET_ARCH = "sh64"
34 default TARGET_sparc if DESIRED_TARGET_ARCH = "sparc"
35 default TARGET_v850 if DESIRED_TARGET_ARCH = "v850"
36 default TARGET_vax if DESIRED_TARGET_ARCH = "vax"
37 default TARGET_x86_64 if DESIRED_TARGET_ARCH = "x86_64"
38 default TARGET_xtensa if DESIRED_TARGET_ARCH = "xtensa"
40 The architecture of your target.
81 config TARGET_microblaze
120 menu "Target Architecture Features and Options"
123 source "extra/Configs/Config.alpha"
127 source "extra/Configs/Config.arm"
131 source "extra/Configs/Config.avr32"
135 source "extra/Configs/Config.bfin"
139 source "extra/Configs/Config.cris"
143 source "extra/Configs/Config.e1"
147 source "extra/Configs/Config.frv"
151 source "extra/Configs/Config.h8300"
155 source "extra/Configs/Config.hppa"
159 source "extra/Configs/Config.i386"
163 source "extra/Configs/Config.i960"
167 source "extra/Configs/Config.ia64"
171 source "extra/Configs/Config.m68k"
175 source "extra/Configs/Config.nios"
179 source "extra/Configs/Config.nios2"
183 source "extra/Configs/Config.microblaze"
187 source "extra/Configs/Config.mips"
191 source "extra/Configs/Config.powerpc"
195 source "extra/Configs/Config.sh"
199 source "extra/Configs/Config.sh64"
203 source "extra/Configs/Config.sparc"
207 source "extra/Configs/Config.v850"
211 source "extra/Configs/Config.vax"
215 source "extra/Configs/Config.x86_64"
219 source "extra/Configs/Config.xtensa"
222 config TARGET_SUBARCH
224 default "e500" if CONFIG_E500
225 default "classic" if CONFIG_CLASSIC
226 default "sh4" if CONFIG_SH4
227 default "" if CONFIG_GENERIC_386 || CONFIG_386
228 default "i486" if CONFIG_486
229 default "i586" if CONFIG_586 || CONFIG_586MMX
230 default "i686" if TARGET_ARCH = "i386"
233 source "extra/Configs/Config.in.arch"
237 menu "General Library Settings"
244 bool "Generate only Position Independent Code (PIC)"
246 depends on !HAVE_NO_PIC
248 If you wish to build all of uClibc as PIC objects, then answer Y here.
249 If you are unsure, then you should answer N.
251 config ARCH_HAS_NO_SHARED
255 config ARCH_HAS_NO_LDSO
257 select ARCH_HAS_NO_SHARED
261 bool "Enable shared libraries"
262 depends on !ARCH_HAS_NO_SHARED
265 If you wish to build uClibc with support for shared libraries then
266 answer Y here. If you only want to build uClibc as a static library,
269 config FORCE_SHAREABLE_TEXT_SEGMENTS
270 bool "Only load shared libraries which can share their text segment"
271 depends on HAVE_SHARED
275 If you answer Y here, the uClibc native shared library loader will
276 only load shared libraries, which do not need to modify any
277 non-writable segments. These libraries haven't set the DT_TEXTREL
278 tag in the dynamic section (==> objdump).
279 All your libraries must be compiled with -fPIC or -fpic, and all
280 assembler function must be written as position independent code (PIC).
281 Enabling this option will make uClibc's shared library loader a
282 little bit smaller and guarantee that no memory will be wasted by
283 badly coded shared libraries.
285 config LDSO_LDD_SUPPORT
286 bool "Native 'ldd' support"
287 depends on HAVE_SHARED
290 Enable all the code needed to support traditional ldd,
291 which executes the shared library loader to resolve all dependencies
292 and then provide a list of shared libraries that are required for an
293 application to function. Disabling this option will make uClibc's
294 shared library loader a little bit smaller.
295 Most people will answer Y.
297 config LDSO_CACHE_SUPPORT
298 bool "Enable library loader cache (ld.so.conf)"
299 depends on HAVE_SHARED
302 Enable this to make use of /etc/ld.so.conf, the shared library loader
303 cache configuration file to support for non-standard library paths.
304 After updating this file, it is necessary to run 'ldconfig' to update
305 the /etc/ld.so.cache shared library loader cache file.
307 config LDSO_PRELOAD_ENV_SUPPORT
308 bool "Enable library loader LD_PRELOAD environment"
309 depends on HAVE_SHARED
312 Enable this to make use of LD_PRELOAD environment variable.
313 A whitespace-separated list of additional, user-specified, ELF shared
314 libraries to be loaded before all others. This can be used to
315 selectively override functions in other shared libraries. For
316 set-user-ID/set-group-ID ELF binaries, only libraries in the standard
317 search directories that are also set-user-ID will be loaded.
319 config LDSO_PRELOAD_FILE_SUPPORT
320 bool "Enable library loader preload file (ld.so.preload)"
321 depends on HAVE_SHARED
324 Enable this to make use of /etc/ld.so.preload. This file contains a
325 whitespace separated list of shared libraries to be loaded before
328 config LDSO_BASE_FILENAME
329 string "Shared library loader naming prefix"
330 depends on HAVE_SHARED && (LDSO_CACHE_SUPPORT || LDSO_PRELOAD_FILE_SUPPORT)
333 If you wish to support both uClibc and glibc on the same system, it
334 is necessary to set this to something other than "ld.so" to avoid
335 conflicts with glibc, which also uses "ld.so". This prevents both
336 libraries from using the same /etc/ld.so.* files. If you wish to
337 support both uClibc and glibc on the same system then you should set
338 this to "ld-uClibc.so".
340 Most people will leave this set to the default of "ld.so".
342 WARNING: Changing the default prefix could cause problems with
345 config UCLIBC_STATIC_LDCONFIG
346 bool "Link ldconfig statically"
347 depends on HAVE_SHARED
350 Enable this option to statically link the ldconfig binary.
352 Making ldconfig static can be beneficial if you have a library
353 problem and need to use ldconfig to recover. Sometimes it is
354 preferable to instead keep the size of the system down, in which
355 case you should disable this option.
358 bool "Enable ELF RUNPATH tag support"
359 depends on HAVE_SHARED
360 default y if LDSO_CACHE_SUPPORT
361 default n if !LDSO_CACHE_SUPPORT
363 ELF's may have dynamic RPATH/RUNPATH tags. These tags list paths
364 which extend the library search paths. They are really only useful
365 if a package installs libraries in non standard locations and
366 ld.so.conf support is disabled.
368 Usage of RUNPATH tags is not too common, so disabling this feature
369 should be safe for most people.
371 config LDSO_SEARCH_INTERP_PATH
372 bool "Add ldso path to lib search path"
373 depends on HAVE_SHARED
376 The ldso is told where it is being executed from and can use that
377 path to find related core libraries. This is useful by default,
378 but can be annoying in a mixed development environment.
380 i.e. if the ldso is run from /foo/boo/ldso.so, it will start its
381 library search with /foo/boo/
383 If unsure, simply say Y here.
385 config UCLIBC_CTOR_DTOR
386 bool "Support global constructors and destructors"
389 If you wish to build uClibc with support for global constructor
390 (ctor) and global destructor (dtor) support, then answer Y here.
391 When ctor/dtor support is enabled, binaries linked with uClibc must
392 also be linked with crtbegin.o and crtend.o which are provided by gcc
393 (the "*startfile:" and "*endfile:" settings in your gcc specs file
394 may need to be adjusted to include these files). This support will
395 also add a small amount of additional size to each binary compiled vs
396 uClibc. If you will be using uClibc with C++, or if you need the gcc
397 __attribute__((constructor)) and __attribute__((destructor)) to work,
398 then you definitely want to answer Y here. If you don't need ctors
399 or dtors and want your binaries to be as small as possible, then
402 config LDSO_GNU_HASH_SUPPORT
403 bool "Enable GNU hash style support"
404 depends on HAVE_SHARED
407 Newest binutils support a new hash style named GNU-hash. The dynamic
408 linker will use the new GNU-hash section (.gnu.hash) for symbol lookup
409 if present into the ELF binaries, otherwise it will use the old SysV
410 hash style (.hash). This ensures that it is completely backward
412 Further, being the hash table implementation self-contained into each
413 executable and shared libraries, objects with mixed hash style can
414 peacefully coexist in the same process.
416 If you want to use this new feature, answer Y
419 prompt "Thread support"
420 #default UCLIBC_HAS_THREADS_NATIVE if (TARGET_alpha || TARGET_arm || TARGET_i386 || TARGET_mips || TARGET_powerpc || TARGET_sh || TARGET_sh64)
421 default HAS_NO_THREADS
423 If you want to compile uClibc with pthread support, then answer Y.
424 This will increase the size of uClibc by adding a bunch of locking
425 to critical data structures, and adding extra code to ensure that
426 functions are properly reentrant.
428 config HAS_NO_THREADS
431 Disable thread support.
433 config LINUXTHREADS_OLD
434 bool "older (stable) version of linuxthreads"
435 # linuxthreads and linuxthreads.old need nanosleep()
436 select UCLIBC_HAS_REALTIME
438 There are two versions of linuxthreads. The older (stable) version
439 has been in uClibc for quite a long time but hasn't seen too many
440 updates other than bugfixes.
443 config LINUXTHREADS_NEW
444 bool "slightly newer version of linuxthreads"
446 The new version has not been tested much, and lacks ports for arches
447 which glibc does not support (like bfin/frv/etc...), but is based on
448 the latest code from glibc, so it may be the only choice for the
449 newer ports (like alpha/amd64/64bit arches and hppa).
451 config UCLIBC_HAS_THREADS_NATIVE
452 bool "Native POSIX Threading (NPTL)"
453 select UCLIBC_HAS_TLS
454 select UCLIBC_HAS_STDIO_FUTEXES
456 select EXTRA_WARNINGS
457 # i386 has no lowlevellock support (yet) as opposed to i486 onward
458 depends on !CONFIG_386
460 If you want to compile uClibc with NPTL support, then answer Y.
462 IMPORTANT NOTE! NPTL requires a Linux 2.6 kernel, binutils
463 at least version 2.16 and GCC with at least version 4.1.0. NPTL
464 will not work with older versions of any above sources. If you
465 ignore any of these guidelines, you do so at your own risk. Do
466 not ask for help on any of the development mailing lists.
468 !!!! WARNING !!!! BIG FAT WARNING !!!! REALLY BIG FAT WARNING !!!!
470 This is experimental code and at times it may not even build and
471 even if it does it might decide to do random damage. This code is
472 potentially hazardous to your health and sanity. It will remain
473 that way until further notice at which point this notice will
474 disappear. Thank you for your support and for not smoking.
478 config UCLIBC_HAS_THREADS
479 def_bool y if !HAS_NO_THREADS
481 config UCLIBC_HAS_TLS
482 bool "Thread-Local Storage"
483 depends on UCLIBC_HAS_THREADS_NATIVE
486 If you want to enable TLS support then answer Y.
487 This is fast an efficient way to store per-thread local data
488 which is not on stack. It needs __thread support enabled in
491 config PTHREADS_DEBUG_SUPPORT
492 bool "Build pthreads debugging support"
494 depends on UCLIBC_HAS_THREADS
496 Say Y here if you wish to be able to debug applications that use
497 uClibc's pthreads library. By enabling this option, a library
498 named libthread_db will be built. This library will be dlopen()'d
499 by gdb and will allow gdb to debug the threads in your application.
501 IMPORTANT NOTE! Because gdb must dlopen() the libthread_db library,
502 you must compile gdb with uClibc in order for pthread debugging to
505 If you are doing development and want to debug applications using
506 uClibc's pthread library, answer Y. Otherwise, answer N.
509 config UCLIBC_HAS_SYSLOG
510 bool "Syslog support"
512 depends on UCLIBC_HAS_NETWORK_SUPPORT
513 select UCLIBC_HAS_SOCKET
515 Support sending messages to the system logger.
516 This requires socket-support.
518 config UCLIBC_HAS_LFS
519 bool "Large File Support"
522 If you wish to build uClibc with support for accessing large files
523 (i.e. files greater then 2 GiB) then answer Y. Do not enable this
524 if you are using an older Linux kernel (2.0.x) that lacks large file
525 support. Enabling this option will increase the size of uClibc.
528 prompt "Malloc Implementation"
529 default MALLOC if ! ARCH_USE_MMU
530 default MALLOC_STANDARD if ARCH_USE_MMU
535 "malloc" use mmap for all allocations and so works very well on
536 MMU-less systems that do not support the brk() system call. It is
537 pretty smart about reusing already allocated memory, and minimizing
539 This is the default for uClinux MMU-less systems.
544 "malloc-simple" is trivially simple and slow as molasses. It
545 was written from scratch for uClibc, and is the simplest possible
546 (and therefore smallest) malloc implementation.
548 This uses only the mmap() system call to allocate and free memory,
549 and does not use the brk() system call at all, making it a fine
550 choice for MMU-less systems with very limited memory. It's 100%
551 standards compliant, thread safe, very small, and releases freed
552 memory back to the OS immediately rather than keeping it in the
553 process's heap for reallocation. It is also VERY SLOW.
555 config MALLOC_STANDARD
556 bool "malloc-standard"
557 depends on ARCH_USE_MMU
559 "malloc-standard" is derived from the public domain dlmalloc
560 implementation by Doug Lea. It is quite fast, and is pretty smart
561 about reusing already allocated memory, and minimizing memory
562 wastage. This uses brk() for small allocations, while using mmap()
563 for larger allocations. This is the default malloc implementation
566 If unsure, answer "malloc-standard".
570 config MALLOC_GLIBC_COMPAT
571 bool "Malloc returns live pointer for malloc(0)"
574 The behavior of malloc(0) is listed as implementation-defined by
575 SuSv3. Glibc returns a valid pointer to something, while uClibc
576 normally returns NULL. I personally feel glibc's behavior is
577 not particularly safe, and allows buggy applications to hide very
580 When this option is enabled, uClibc will act just like glibc, and
581 return a live pointer when someone calls malloc(0). This pointer
582 provides a malloc'ed area with a size of 1 byte. This feature is
583 mostly useful when dealing with applications using autoconf's broken
584 AC_FUNC_MALLOC macro (which redefines malloc as rpl_malloc if it
585 does not detect glibc style returning-a-valid-pointer-for-malloc(0)
586 behavior). Most people can safely answer N.
588 config UCLIBC_DYNAMIC_ATEXIT
589 bool "Dynamic atexit() Support"
592 When this option is enabled, uClibc will support an infinite number,
593 of atexit() and on_exit() functions, limited only by your available
594 memory. This can be important when uClibc is used with C++, since
595 global destructors are implemented via atexit(), and it is quite
596 possible to exceed the default number when this option is disabled.
597 Enabling this option adds a few bytes, and more significantly makes
598 atexit and on_exit depend on malloc, which can be bad when compiling
601 Unless you use uClibc with C++, you should probably answer N.
604 bool "Old (visible) atexit Support"
607 Enable this option if you want to update from 0.9.28 to git/0.9.29,
608 else you will be missing atexit() until you rebuild all apps.
610 config UCLIBC_SUSV3_LEGACY
611 bool "Enable SuSv3 LEGACY functions"
618 Enable this option if you want to have SuSv3 LEGACY functions
619 in the library, else they are replaced by SuSv3 proposed macros.
620 Currently applies to:
622 bcmp, bcopy, bzero, index, rindex, ftime,
623 bsd_signal, (ecvt), (fcvt), gcvt, (getcontext),
624 (getwd), (makecontext),
625 mktemp, (pthread_attr_getstackaddr), (pthread_attr_setstackaddr),
626 scalb, (setcontext), (swapcontext), ualarm, usleep,
629 WARNING! ABI incompatibility.
631 config UCLIBC_SUSV3_LEGACY_MACROS
632 bool "Enable SuSv3 LEGACY macros"
635 Enable this option if you want to have SuSv3 LEGACY macros.
636 Currently applies to bcopy/bzero/bcmp/index/rindex et al.
637 WARNING! ABI incompatibility.
639 config UCLIBC_SUSV4_LEGACY
640 bool "Enable SuSv4 LEGACY or obsolescent functions"
643 Enable this option if you want to have SuSv4 LEGACY functions
644 and macros in the library.
645 Currently applies to:
648 _longjmp, _setjmp, _tolower, _toupper, ftw, getitimer,
649 gettimeofday, isascii, pthread_getconcurrency,
650 pthread_setconcurrency, setitimer, setpgrp, sighold,
651 sigignore, sigpause, sigrelse, sigset, siginterrupt,
652 tempnam, toascii, ulimit.
655 asctime, asctime_r, ctime, ctime_r, gets, rand_r,
658 WARNING! ABI incompatibility.
660 config UCLIBC_HAS_STUBS
661 bool "Provide stubs for unavailable functionality"
664 With this option uClibc provides non-functional stubs for
665 functions which are impossible to implement on the target
666 architecture. Otherwise, such functions are simply omitted.
668 As of 2008-07, this option makes uClibc provide fork() stub
669 on NOMMU targets. It always sets errno to ENOSYS and returns -1.
671 This may be useful if you port a lot of software and cannot
672 audit all of it and replace or disable fork() usage.
673 With this option, a program which uses fork() will build
674 successfully. Of course, it may be useless if fork()
675 is essential for its operation.
677 config UCLIBC_HAS_SHADOW
678 bool "Shadow Password Support"
681 Answer N if you do not need shadow password support.
682 Most people will answer Y.
684 config UCLIBC_HAS_PROGRAM_INVOCATION_NAME
685 bool "Support for program_invocation_name"
688 Support for the GNU-specific program_invocation_name and
689 program_invocation_short_name strings. Some GNU packages
690 (like tar and coreutils) utilize these for extra useful
691 output, but in general are not required.
693 At startup, these external strings are automatically set
694 up based on the value of ARGV[0].
696 If unsure, just answer N.
698 config UCLIBC_HAS___PROGNAME
699 bool "Support for __progname"
701 depends on UCLIBC_HAS_PROGRAM_INVOCATION_NAME
703 Some packages (like openssh) like to peek into internal libc
704 symbols to make their output a bit more user friendly.
706 At startup, __progname is automatically set up based on the
709 If unsure, just answer N.
711 config UCLIBC_HAS_PTY
712 bool "Support for pseudo-terminals"
715 This enables support for pseudo-terminals (see man 4 pts
718 If unsure, just answer Y.
721 bool "Assume that /dev/pts is a devpts or devfs file system"
723 depends on UCLIBC_HAS_PTY
725 Enable this if /dev/pts is on a devpts or devfs filesystem. Both
726 these filesystems automatically manage permissions on the /dev/pts
727 devices. You may need to mount your devpts or devfs filesystem on
728 /dev/pts for this to work.
730 Most people should answer Y.
732 config UNIX98PTY_ONLY
733 bool "Support only Unix 98 PTYs"
735 depends on UCLIBC_HAS_PTY
737 If you want to support only Unix 98 PTYs enable this. Some older
738 applications may need this disabled and will thus use legacy BSD
739 style PTY handling which is more complex and also bigger than
740 Unix 98 PTY handling.
742 For most current programs, you can generally answer Y.
745 config UCLIBC_HAS_GETPT
746 bool "Support getpt() (glibc-compat)"
748 depends on UCLIBC_HAS_PTY
750 Some packages may need getpt().
751 All of those are non-standard and can be considered
752 GNU/libc compatibility.
753 Either use posix_openpt() or just open /dev/ptmx yourself.
755 If unsure, just say N.
759 # Have to use __libc_ptyname{1,2}[] and related bloat
760 config UCLIBC_HAS_GETPT
764 config UCLIBC_HAS_LIBUTIL
765 bool "Provide libutil library and functions"
766 depends on UCLIBC_HAS_PTY
769 Provide a libutil library.
770 This non-standard conforming library provides the following
773 forkpty(): combines openpty(), fork(2), and login_tty() to
774 create a new process operating in a pseudo-terminal.
775 login(): write utmp and wtmp entries
776 login_tty(): prepares for a login on the tty fd by creating a
777 new session, making fd the controlling terminal for
778 the calling process, setting fd to be the standard
779 input, output, and error streams of the current
780 process, and closing fd.
781 logout(): write utmp and wtmp entries
782 logwtmp(): constructs a utmp structure and calls updwtmp() to
783 append the structure to the utmp file.
784 openpty(): finds an available pseudo-terminal and returns
785 file descriptors for the master and slave
787 This library adds about 3k-4k to your system.
789 config UCLIBC_HAS_TM_EXTENSIONS
790 bool "Support 'struct tm' timezone extension fields"
793 Enabling this option adds fields to 'struct tm' in time.h for
794 tracking the number of seconds east of UTC, and an abbreviation for
795 the current timezone. These fields are not specified by the SuSv3
796 standard, but they are commonly used in both GNU and BSD application
799 To strictly follow the SuSv3 standard, leave this disabled.
800 Most people will probably want to answer Y.
802 config UCLIBC_HAS_TZ_CACHING
803 bool "Enable caching of the last valid timezone 'TZ' string"
806 Answer Y to enable caching of the last valid 'TZ' string describing
807 the timezone setting. This allows a quick string compare to avoid
808 repeated parsing of unchanged 'TZ' strings when tzset() is called.
810 Most people will answer Y.
812 config UCLIBC_HAS_TZ_FILE
813 bool "Enable '/etc/TZ' file support to set a default timezone (uClibc-specific)"
816 Answer Y to enable the setting of a default timezone for uClibc.
818 Ordinarily, uClibc gets the timezone information exclusively from the
819 'TZ' environment variable. In particular, there is no support for
820 the zoneinfo directory tree or the /etc/timezone file used by glibc.
822 With this option enabled, uClibc will use the value stored in the
823 file '/etc/TZ' (default path) to obtain timezone information if the
824 'TZ' environment variable is missing or has an invalid value. The
825 file consists of a single line (newline required) of text describing
826 the timezone in the format specified for the TZ environment variable.
828 Doing 'echo CST6CDT > /etc/TZ' is enough to create a valid file.
830 http://www.opengroup.org/onlinepubs/007904975/basedefs/xbd_chap08.html
831 for details on valid settings of 'TZ'.
833 Most people will answer Y.
835 config UCLIBC_HAS_TZ_FILE_READ_MANY
836 bool "Repeatedly read the '/etc/TZ' file"
837 depends on UCLIBC_HAS_TZ_FILE
840 Answer Y to enable repeated reading of the '/etc/TZ' file even after
841 a valid value has been read. This incurs the overhead of an
842 open/read/close for each tzset() call (explicit or implied). However,
843 setting this will allow applications to update their timezone
844 information if the contents of the file change.
846 Most people will answer Y.
848 config UCLIBC_TZ_FILE_PATH
849 string "Path to the 'TZ' file for setting the global timezone"
850 depends on UCLIBC_HAS_TZ_FILE
853 This is the path to the 'TZ' file.
855 Most people will use the default of '/etc/TZ'.
857 config UCLIBC_FALLBACK_TO_ETC_LOCALTIME
858 bool "Use /etc/localtime as a fallback"
859 depends on UCLIBC_HAS_TZ_FILE
862 Answer Y to try to use /etc/localtime file.
863 On glibc systems this file (if it is in TZif2 format)
864 contains timezone string at the end.
866 Most people will answer Y.
870 menu "Advanced Library Settings"
872 config UCLIBC_PWD_BUFFER_SIZE
873 int "Buffer size for getpwnam() and friends"
877 This sets the value of the buffer size for getpwnam() and friends.
878 By default, this is 256. (For reference, glibc uses 1024).
879 The value can be found using sysconf() with the _SC_GETPW_R_SIZE_MAX
882 config UCLIBC_GRP_BUFFER_SIZE
883 int "Buffer size for getgrnam() and friends"
887 This sets the value of the buffer size for getgrnam() and friends.
888 By default, this is 256. (For reference, glibc uses 1024).
889 The value can be found using sysconf() with the _SC_GETGR_R_SIZE_MAX
892 comment "Support various families of functions"
894 config UCLIBC_LINUX_MODULE_24
895 bool "Linux kernel module functions"
896 default !(TARGET_bfin)
898 create_module, query_module
899 are used in linux (prior to 2.6) for loadable kernel modules.
901 Say N if you do not use kernel modules, or you only support
904 config UCLIBC_LINUX_SPECIFIC
905 bool "Linux specific functions"
908 capget(), capset(), fstatfs(), inotify_*(), ioperm(), iopl(),
909 madvise(), modify_ldt(), personality(), prctl()/arch_prctl(),
910 ppoll(), readahead(), reboot(), remap_file_pages(),
911 sched_getaffinity(), sched_setaffinity(), sendfile(),
912 setfsgid(), setfsuid(), setresuid(),
913 splice(), vmsplice(), tee(), signalfd(), swapoff(), swapon(),
914 sync_file_range(), sysctl(), sysinfo(), vhangup()
916 config UCLIBC_HAS_GNU_ERROR
917 bool "Support GNU extensions for error-reporting"
920 Support for the GNU-specific error(), error_at_line(),
921 void (* error_print_progname)(), error_message_count
922 functions and variables. Some GNU packages
923 utilize these for extra useful output, but in general
926 If unsure, just answer N.
928 config UCLIBC_BSD_SPECIFIC
929 bool "BSD specific functions"
932 mincore(), getdomainname(), setdomainname()
936 config UCLIBC_HAS_BSD_ERR
937 bool "BSD err functions"
940 These functions are non-standard BSD extensions.
941 err(), errx(), warn(), warnx(), verr(), verrx(), vwarn(), vwarnx()
945 config UCLIBC_HAS_OBSOLETE_BSD_SIGNAL
946 bool "BSD obsolete signal functions"
949 These functions are provided as a compatibility interface for
950 programs that make use of the historical System V signal API.
951 This API is obsolete:
952 new applications should use the POSIX signal API (sigaction(2),
953 sigprocmask(2), etc.).
956 sigset(), sighold(), sigrelse(), sigignore()
960 config UCLIBC_HAS_OBSOLETE_SYSV_SIGNAL
961 bool "SYSV obsolete signal functions"
964 Use of sysv_signal() should be avoided; use sigaction(2) instead.
968 config UCLIBC_NTP_LEGACY
969 bool "ntp_*() aliases"
972 Provide legacy aliases for ntp functions:
973 ntp_adjtime(), ntp_gettime()
975 It is safe to say N here.
977 config UCLIBC_SV4_DEPRECATED
978 bool "Enable SVr4 deprecated functions"
981 These functions are DEPRECATED in System V release 4.
982 Say N unless you desparately need one of the functions below:
984 ustat() [use statfs(2) in your code instead]
986 config UCLIBC_HAS_REALTIME
987 bool "Realtime-related family of SUSv functions"
990 These functions are part of the Timers option and need not
991 be available on all implementations.
992 Includes AIO, message-queue, scheduler, semaphore functions:
1007 clock_getres(), clock_gettime(), clock_settime()
1009 mlockall(), munlockall()
1021 sched_get_priority_max(), sched_get_priority_min()
1022 sched_getscheduler()
1023 sched_rr_get_interval()
1025 sched_setscheduler()
1032 sem_trywait(), sem_wait()
1035 sigtimedwait(), sigwaitinfo()
1038 timer_getoverrun(), timer_gettime(), timer_settime()
1040 config UCLIBC_HAS_ADVANCED_REALTIME
1041 bool "Advanced realtime-related family of SUSv functions"
1043 depends on UCLIBC_HAS_REALTIME
1045 These functions are part of the Timers option and need not
1046 be available on all implementations.
1048 clock_getcpuclockid()
1057 posix_spawnattr_destroy(), posix_spawnattr_init()
1058 posix_spawnattr_getflags(), posix_spawnattr_setflags()
1059 posix_spawnattr_getpgroup(), posix_spawnattr_setpgroup()
1060 posix_spawnattr_getschedparam(), posix_spawnattr_setschedparam()
1061 posix_spawnattr_getschedpolicy(), posix_spawnattr_setschedpolicy()
1062 posix_spawnattr_getsigdefault(), posix_spawnattr_setsigdefault()
1063 posix_spawnattr_getsigmask(), posix_spawnattr_setsigmask()
1064 posix_spawn_file_actions_addclose()
1065 posix_spawn_file_actions_adddup2()
1066 posix_spawn_file_actions_addopen()
1067 posix_spawn_file_actions_destroy()
1068 posix_spawn_file_actions_init()
1071 posix_typed_mem_get_info()
1072 pthread_mutex_timedlock()
1075 #config UCLIBC_HAS_TERMIOS
1076 # bool "termios functions"
1079 # Get and set terminal attributes, line control, get and set baud
1081 # termios(), tcgetattr(), tcsetattr(), tcsendbreak(), tcdrain(),
1082 # tcflush(), tcflow(), cfmakeraw(), cfgetospeed(), cfgetispeed(),
1083 # cfsetispeed(), cfsetospeed(), cfsetspeed()
1087 config UCLIBC_HAS_EPOLL
1091 epoll_create(), epoll_ctl(), epoll_wait() functions.
1093 config UCLIBC_HAS_XATTR
1094 bool "Extended Attributes"
1097 Extended Attributes support.
1112 Say N unless you need support for extended attributes and the
1113 filesystems do actually support them.
1115 config UCLIBC_HAS_PROFILING
1116 bool "Profiling support"
1119 gcc's -finstrument-functions needs these.
1121 Most people can safely answer N.
1123 config UCLIBC_HAS_CRYPT_IMPL
1124 bool "libcrypt support"
1127 libcrypt contains crypt(), setkey() and encrypt()
1129 config UCLIBC_HAS_CRYPT_STUB
1130 bool "libcrypt stubs"
1132 depends on !UCLIBC_HAS_CRYPT_IMPL
1134 Standards mandate that crypt(3) provides a stub if it is unavailable.
1135 If you enable this option then stubs for
1136 crypt(), setkey() and encrypt()
1137 will be provided in a small libcrypt.
1139 config UCLIBC_HAS_CRYPT
1141 depends on UCLIBC_HAS_CRYPT_IMPL || UCLIBC_HAS_CRYPT_STUB
1144 menuconfig UCLIBC_HAS_NETWORK_SUPPORT
1145 bool "Networking Support"
1148 Say N here if you do not need network support.
1150 if UCLIBC_HAS_NETWORK_SUPPORT
1151 config UCLIBC_HAS_SOCKET
1152 bool "Socket support"
1155 If you want to include support for sockets then answer Y.
1157 config UCLIBC_HAS_IPV4
1158 bool "IP version 4 support"
1160 select UCLIBC_HAS_SOCKET
1162 If you want to include support for the Internet Protocol
1163 (IP version 4) then answer Y.
1165 Most people will say Y.
1167 config UCLIBC_HAS_IPV6
1168 bool "IP version 6 support"
1170 select UCLIBC_HAS_SOCKET
1172 If you want to include support for the next version of the Internet
1173 Protocol (IP version 6) then answer Y.
1175 Most people should answer N.
1177 config UCLIBC_HAS_RPC
1178 bool "Remote Procedure Call (RPC) support"
1180 # RPC+socket-ipvX doesn't currently work.
1181 depends on UCLIBC_HAS_IPV4 || UCLIBC_HAS_IPV6
1183 If you want to include RPC support, enable this. RPC is rarely used
1184 for anything except for the NFS filesystem. Unless you plan to use
1185 NFS, you can probably leave this set to N and save some space.
1187 If you need to use NFS then you should answer Y.
1189 config UCLIBC_HAS_FULL_RPC
1190 bool "Full RPC support"
1191 depends on UCLIBC_HAS_RPC
1192 default y if !HAVE_SHARED
1194 Normally we enable just enough RPC support for things like rshd and
1195 nfs mounts to work. If you find you need the rest of the RPC stuff,
1196 then enable this option. Most people can safely answer N.
1198 config UCLIBC_HAS_REENTRANT_RPC
1199 bool "Reentrant RPC support"
1200 depends on UCLIBC_HAS_RPC
1201 default y if !HAVE_SHARED
1203 Most packages utilize the normal (non-reentrant) RPC functions, but
1204 some (like exportfs from nfs-utils) need these reentrant versions.
1206 Most people can safely answer N.
1208 config UCLIBC_USE_NETLINK
1209 bool "Use netlink to query interfaces"
1211 depends on UCLIBC_HAS_SOCKET
1213 In newer versions of Linux (2.4.17+), support was added for querying
1214 network device information via netlink rather than the old style
1215 ioctl's. Most of the time, the older ioctl style is sufficient (and
1216 it is smaller than netlink), but if you find that not all of your
1217 devices are being returned by the if_nameindex() function, you will
1218 have to use the netlink implementation.
1220 Most people can safely answer N.
1222 config UCLIBC_SUPPORT_AI_ADDRCONFIG
1223 bool "Support the AI_ADDRCONFIG flag"
1224 depends on UCLIBC_USE_NETLINK
1227 The implementation of AI_ADDRCONFIG is aligned with the glibc
1228 implementation using netlink to query interfaces to find both
1229 ipv4 and ipv6 support. This is only needed if an application uses
1230 the AI_ADDRCONFIG flag.
1232 Most people can safely answer N.
1234 config UCLIBC_HAS_BSD_RES_CLOSE
1235 bool "Support res_close() (bsd-compat)"
1238 Answer Y if you desperately want to support BSD compatibility in
1241 Most people will say N.
1243 config UCLIBC_HAS_COMPAT_RES_STATE
1244 bool "Use compatible but bloated _res"
1247 Answer Y if you build network utilities and they muck with resolver
1248 internals a lot (_res global structure). uclibc does not use most
1249 of _res.XXX fields, and with this option OFF they won't even exist.
1250 Which will make e.g. dig build fail.
1251 Answering N saves around 400 bytes in bss.
1253 config UCLIBC_HAS_EXTRA_COMPAT_RES_STATE
1254 bool "Use extra compatible but extra bloated _res"
1257 Answer Y if selecting UCLIBC_HAS_COMPAT_RES_STATE is not enough.
1258 As far as I can say, this should never be needed.
1260 config UCLIBC_HAS_LIBRESOLV_STUB
1261 bool "Provide libresolv stub"
1264 Provide a dummy resolv library.
1266 config UCLIBC_HAS_LIBNSL_STUB
1267 bool "Provide libnsl stub"
1270 Provide a dummy nsl library.
1275 menu "String and Stdio Support"
1277 config UCLIBC_HAS_STRING_GENERIC_OPT
1278 bool "Use faster (but larger) generic string functions"
1281 Answer Y to use the (tweaked) glibc generic string functions.
1283 In general, they are faster (but 3-5K larger) than the base
1284 uClibc string functions which are optimized solely for size.
1286 Many people will answer Y.
1288 config UCLIBC_HAS_STRING_ARCH_OPT
1289 bool "Use arch-specific assembly string functions (where available)"
1292 Answer Y to use any archtecture-specific assembly language string
1293 functions available for this target plaform.
1295 Note that assembly implementations are not available for all string
1296 functions, so some generic (written in C) string functions may
1299 These are small and fast, the only reason _not_ to say Y here is
1300 for debugging purposes.
1302 config UCLIBC_HAS_CTYPE_TABLES
1303 bool "Use Table Versions Of 'ctype.h' Functions."
1306 Answer Y to use table versions of the 'ctype.h' functions.
1307 While the non-table versions are often smaller when building
1308 statically linked apps, they work only in stub locale mode.
1310 Most people will answer Y.
1312 config UCLIBC_HAS_CTYPE_SIGNED
1313 bool "Support Signed Characters In 'ctype.h' Functions."
1314 depends on UCLIBC_HAS_CTYPE_TABLES
1317 Answer Y to enable support for passing signed char values to
1318 the 'ctype.h' functions. ANSI/ISO C99 and SUSv3 specify that
1319 these functions are only defined for unsigned char values and
1320 EOF. However, glibc allows negative signed char values as well
1321 in order to support 'broken old programs'.
1323 Most people will answer Y.
1326 prompt "ctype argument checking"
1327 depends on UCLIBC_HAS_CTYPE_TABLES
1328 default UCLIBC_HAS_CTYPE_UNSAFE
1330 Please select the invalid arg behavior you want for the 'ctype'
1333 The 'ctype' functions are now implemented using table lookups, with
1334 the arg being the index. This can result in incorrect memory accesses
1335 or even segfaults for args outside of the allowed range.
1337 NOTE: This only affects the 'ctype' _functions_. It does not affect
1338 the macro implementations.
1340 config UCLIBC_HAS_CTYPE_UNSAFE
1341 bool "Do not check -- unsafe"
1343 config UCLIBC_HAS_CTYPE_CHECKED
1344 bool "Detect and handle appropriately"
1346 config UCLIBC_HAS_CTYPE_ENFORCED
1347 bool "Issue a diagnostic and abort()"
1352 config UCLIBC_HAS_WCHAR
1353 bool "Wide Character Support"
1356 Answer Y to enable wide character support. This will make uClibc
1357 much larger. It is also currently required for locale support.
1359 Most people will answer N.
1361 config UCLIBC_HAS_LOCALE
1362 bool "Locale Support"
1363 select UCLIBC_HAS_WCHAR
1364 select UCLIBC_HAS_CTYPE_TABLES
1367 uClibc now has full ANSI/ISO C99 locale support (except for
1368 wcsftime() and collating items in regex). Be aware that enabling
1369 this option will make uClibc much larger.
1371 Enabling UCLIBC_HAS_LOCALE with the default set of supported locales
1372 (169 UTF-8 locales, and 144 locales for other codesets) will enlarge
1373 uClibc by around 300k. You can reduce this size by building your own
1374 custom set of locate data (see extra/locale/LOCALES for details).
1376 uClibc's locale support is still under development. For example,
1377 codesets using shift states are not currently supported. Support is
1378 planned in the next iteration of locale support.
1380 Answer Y to enable locale support. Most people will answer N.
1384 prompt "Locale data"
1385 depends on UCLIBC_HAS_LOCALE
1386 default UCLIBC_BUILD_ALL_LOCALE
1388 config UCLIBC_BUILD_ALL_LOCALE
1390 depends on UCLIBC_HAS_LOCALE
1392 This builds all the locales that are available on your
1395 config UCLIBC_BUILD_MINIMAL_LOCALE
1396 bool "Only selected locales"
1397 depends on UCLIBC_HAS_LOCALE
1399 If you do not need all locales that are available on your
1400 host-box, then set this to 'Y'.
1402 config UCLIBC_PREGENERATED_LOCALE_DATA
1403 bool "Use Pre-generated Locale Data"
1404 depends on UCLIBC_HAS_LOCALE
1406 Use pre-built locale data.
1408 Note that these pregenerated locales are sensitive to your
1409 target architecture (endianess, bitcount).
1411 Saying N here is highly recommended.
1415 config UCLIBC_BUILD_MINIMAL_LOCALES
1416 string "locales to use"
1417 depends on UCLIBC_BUILD_MINIMAL_LOCALE
1420 Space separated list of locales to use.
1427 config UCLIBC_DOWNLOAD_PREGENERATED_LOCALE_DATA
1428 bool "Automagically Download the Pre-generated Locale Data (if necessary)"
1429 depends on UCLIBC_PREGENERATED_LOCALE_DATA
1432 If you would like the build process to use 'wget' to automatically
1433 download the pregenerated locale data, enable this option. Otherwise
1434 you will need to obtain the locale data yourself from:
1435 http://www.uclibc.org/downloads/uClibc-locale-*.tgz
1436 and place the uClibc-locale-*.tgz tarball in the extra/locale/
1439 Note that the use of pregenerated locale data is discouraged.
1441 config UCLIBC_HAS_XLOCALE
1442 bool "Extended Locale Support (experimental/incomplete)"
1443 depends on UCLIBC_HAS_LOCALE
1446 Answer Y to enable extended locale support similar to that provided
1447 by glibc. This is primarily intended to support libstd++
1449 However, it also allows thread-specific locale selection via
1452 Most people will answer N.
1454 config UCLIBC_HAS_HEXADECIMAL_FLOATS
1455 bool "Support hexadecimal float notation"
1456 depends on UCLIBC_HAS_CTYPE_TABLES
1457 depends on UCLIBC_HAS_FLOATS
1460 Answer Y to enable support for hexadecimal float notation in the
1461 (wchar and) char string to floating point conversion functions, as
1462 well as support for the %a and %A conversion specifiers in the
1463 *printf() and *scanf() functions.
1465 Most people will answer N.
1467 config UCLIBC_HAS_GLIBC_DIGIT_GROUPING
1468 bool "Support glibc's \"'\" flag for allowing locale-specific digit grouping"
1469 depends on UCLIBC_HAS_LOCALE
1470 depends on UCLIBC_HAS_FLOATS
1473 Answer Y to enable support for glibc's \"'\" flag for allowing
1474 locale-specific digit grouping in base 10 integer conversions and
1475 appropriate floating point conversions in the *printf() and *scanf()
1478 Most people will answer N.
1480 config UCLIBC_HAS_SCANF_LENIENT_DIGIT_GROUPING
1481 bool "Do not require digit grouping when the \"'\" flag is specified"
1482 depends on UCLIBC_HAS_GLIBC_DIGIT_GROUPING
1485 Answer Y to make digit grouping optional when the \"'\" flag is
1487 This is the standard glibc behavior. If the initial string of digits
1488 exceeds the maximum group number, the input will be treated as a
1489 normal non-grouped number.
1491 Most people will answer N.
1493 config UCLIBC_HAS_GLIBC_CUSTOM_PRINTF
1494 bool "Support glibc's register_printf_function() (glibc-compat)"
1495 depends on !USE_OLD_VFPRINTF
1498 Answer Y to support glibc's register_printf_function() to allow an
1499 application to add its own printf conversion specifiers.
1501 NOTE: Limits the number or registered specifiers to 10.
1502 NOTE: Requires new conversion specifiers to be ASCII
1503 characters (0-0x7f). This is to avoid problems with processing
1504 format strings in locales with different multibyte conversions.
1506 Most people will answer N.
1508 config USE_OLD_VFPRINTF
1509 bool "Use the old vfprintf implementation"
1510 depends on !UCLIBC_HAS_WCHAR
1513 Set to true to use the old vfprintf instead of the new. This is
1514 roughly C89 compliant with some extensions, and is much smaller.
1515 However, it does not support wide chars, positional args, or glibc
1516 custom printf specifiers.
1518 Most people will answer N.
1520 config UCLIBC_PRINTF_SCANF_POSITIONAL_ARGS
1521 int "Maximum number of positional args. Either 0 or >= 9."
1522 depends on !USE_OLD_VFPRINTF
1525 Set the maximum number of positional args supported by the
1526 printf/scanf functions. The Single Unix Specification Version 3
1527 requires a minimum value of 9. Setting this to a value lower than
1528 9 will disable positional arg support and cause the NL_ARGMAX macro
1529 in limits.h to be #undef'd.
1531 WARNING! The workspace to support positional args is currently
1532 allocated on the stack. You probably don't want to set
1533 this to too high a value.
1535 Most people will answer 9.
1538 config UCLIBC_HAS_SCANF_GLIBC_A_FLAG
1539 bool "Support glibc's 'a' flag for scanf string conversions (not implemented)"
1542 NOTE!!! Currently Not Implemented!!! Just A Place Holder!! NOTE!!!
1543 NOTE!!! Conflicts with an ANSI/ISO C99 scanf flag!! NOTE!!!
1545 Answer Y to enable support for glibc's 'a' flag for the scanf string
1546 conversions '%s', '%[', '%ls', '%l[', and '%S'. This is used to
1547 auto-allocate sufficient memory to hold the data retrieved.
1549 Most people will answer N.
1552 prompt "Stdio buffer size"
1553 default UCLIBC_HAS_STDIO_BUFSIZ_4096
1555 Please select a value for BUFSIZ. This will be used by the
1556 stdio subsystem as the default buffer size for a file, and
1557 affects fopen(), setvbuf(), etc.
1559 NOTE: Setting this to 'none' will disable buffering completely.
1560 However, BUFSIZ will still be defined in stdio.h as 256 because
1561 many applications use this value.
1563 config UCLIBC_HAS_STDIO_BUFSIZ_NONE
1564 bool "none (WARNING - BUFSIZ will be 256 in stdio.h)"
1565 depends on !UCLIBC_HAS_WCHAR
1567 config UCLIBC_HAS_STDIO_BUFSIZ_256
1568 bool "256 (minimum ANSI/ISO C99 value)"
1570 config UCLIBC_HAS_STDIO_BUFSIZ_512
1573 config UCLIBC_HAS_STDIO_BUFSIZ_1024
1576 config UCLIBC_HAS_STDIO_BUFSIZ_2048
1579 config UCLIBC_HAS_STDIO_BUFSIZ_4096
1582 config UCLIBC_HAS_STDIO_BUFSIZ_8192
1585 # If you add more choices, you will need to update uClibc_stdio.h.
1590 prompt "Stdio builtin buffer size (uClibc-specific)"
1591 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1592 default UCLIBC_HAS_STDIO_BUILTIN_BUFFER_NONE
1594 When a FILE is created with fopen(), an attempt is made to allocate
1595 a BUFSIZ buffer for it. If the allocation fails, fopen() will still
1596 succeed but the FILE will be unbuffered.
1598 This option adds a small amount of space to each FILE to act as an
1599 emergency buffer in the event of a buffer allocation failure.
1601 Most people will answer None.
1603 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_NONE
1606 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_4
1609 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_8
1612 # If you add more choices, you will need to update uClibc_stdio.h.
1616 config UCLIBC_HAS_STDIO_SHUTDOWN_ON_ABORT
1617 bool "Attempt to shutdown stdio subsystem when abort() is called."
1620 ANSI/ISO C99 requires abort() to be asyn-signal-safe. So there was
1621 a behavioral change made in SUSv3. Previously, abort() was required
1622 to have the affect of fclose() on all open streams. The wording has
1623 been changed to "may" from "shall".
1625 Most people will answer N.
1627 config UCLIBC_HAS_STDIO_GETC_MACRO
1628 bool "Provide a macro version of getc()"
1629 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1632 Provide a macro version of getc().
1634 Most people will answer Y.
1636 config UCLIBC_HAS_STDIO_PUTC_MACRO
1637 bool "Provide a macro version of putc()"
1638 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1641 Provide a macro version of putc().
1643 Most people will answer Y.
1645 config UCLIBC_HAS_STDIO_AUTO_RW_TRANSITION
1646 bool "Support auto-r/w transition"
1649 Answer Y to enable the stdio subsystem to automaticly transition
1650 between reading and writing. This relaxes the ANSI/ISO C99
1653 When a file is opened with update mode ('+' as the second or third
1654 character in the list of mode argument values), both input and output
1655 may be performed on the associated stream. However, output shall not
1656 be directly followed by input without an intervening call to the
1657 fflush function or to a file positioning function (fseek, fsetpos,
1658 or rewind), and input shall not be directly followed by output without
1659 an intervening call to a file positioning function, unless the input
1660 operation encounters endÂofÂfile.
1662 Most people will answer Y.
1664 config UCLIBC_HAS_FOPEN_LARGEFILE_MODE
1665 bool "Support an fopen() 'F' flag for large file mode (uClibc-specific)"
1666 depends on UCLIBC_HAS_LFS
1669 Answer Y to enable a uClibc-specific extension to allow passing an
1670 additional 'F' flag in the mode string for fopen() to specify that
1671 the file should be open()ed with the O_LARGEFILE flag set.
1673 Most people will answer N.
1675 config UCLIBC_HAS_FOPEN_EXCLUSIVE_MODE
1676 bool "Support an fopen() 'x' flag for exclusive mode (glibc-compat)"
1679 Answer Y to support a glibc extension to allow passing
1680 additional 'x' flag in the mode string for fopen() to specify that
1681 the file should be open()ed with the O_EXCL flag set.
1683 Most people will answer N.
1685 config UCLIBC_HAS_GLIBC_CUSTOM_STREAMS
1686 bool "Support fmemopen(), open_memstream(), and fopencookie() (glibc-compat)"
1689 Answer Y to support the glibc 'custom stream' extension functions
1690 fmemopen(), open_memstream(), and fopencookie().
1692 NOTE: There are some minor differences regarding seeking behavior.
1694 Most people will answer N.
1696 config UCLIBC_HAS_PRINTF_M_SPEC
1697 bool "Support the '%m' specifier in printf format strings (glibc-compat)"
1700 Answer Y to support a glibc extension to interpret '%m' in printf
1701 format strings as an instruction to output the error message string
1702 (as generated by strerror) corresponding to the current value of
1705 Most people will answer N.
1707 config UCLIBC_HAS_ERRNO_MESSAGES
1708 bool "Include the errno message text in the library"
1711 Answer Y if you want to include the errno message text in the
1712 library. This adds about 3K to the library, but enables strerror()
1713 to generate text other than 'Unknown error <number>'.
1715 Most people will answer Y.
1717 config UCLIBC_HAS_SYS_ERRLIST
1718 bool "Support sys_errlist[] (obsolete-compat)"
1719 depends on UCLIBC_HAS_ERRNO_MESSAGES
1722 Answer Y if you want to support the obsolete sys_errlist[].
1723 This adds about 0.5k to the library, except for the mips
1724 arch where it adds over 4K.
1726 WARNING! In the future, support for sys_errlist[] may be unavailable
1727 in at least some configurations. In fact, it may be removed
1730 Most people will answer N.
1732 Application writers: use the strerror(3) function.
1734 config UCLIBC_HAS_SIGNUM_MESSAGES
1735 bool "Include the signum message text in the library"
1738 Answer Y if you want to include the signum message text in the
1739 library. This adds about 0.5K to the library, but enables strsignal()
1740 to generate text other than 'Unknown signal <number>'.
1742 Most people will answer Y.
1744 config UCLIBC_HAS_SYS_SIGLIST
1745 bool "Support sys_siglist[] (bsd-compat)"
1746 depends on UCLIBC_HAS_SIGNUM_MESSAGES
1749 Answer Y if you want to support sys_siglist[].
1751 WARNING! In the future, support for sys_siglist[] may be unavailable
1752 in at least some configurations. In fact, it may be removed
1755 Most people will answer N.
1757 config UCLIBC_HAS_GETTEXT_AWARENESS
1758 bool "Include gettext awareness"
1759 depends on UCLIBC_HAS_LOCALE && UCLIBC_MJN3_ONLY
1762 NOTE!!! Not yet integrated with strerror and strsignal. NOTE!!!
1764 Answer Y if you want to include weak stub gettext support and
1765 make the *strerror*() and strsignal() functions gettext-aware.
1767 Currently, to get functional gettext functionality you will need
1770 Most people will answer N.
1772 config UCLIBC_HAS_GNU_GETOPT
1773 bool "Support gnu getopt"
1776 Answer Y if you want to include full gnu getopt() instead of a
1777 (much smaller) SUSv3 compatible getopt().
1779 Most people will answer Y.
1781 config UCLIBC_HAS_STDIO_FUTEXES
1782 bool "Use futexes for multithreaded I/O locking"
1784 depends on UCLIBC_HAS_THREADS_NATIVE
1786 If you want to compile uClibc to use futexes for low-level
1787 I/O locking, answer Y. Otherwise, answer N.
1789 config UCLIBC_HAS_GETOPT_LONG
1790 bool "Support getopt_long/getopt_long_only"
1791 depends on !UCLIBC_HAS_GNU_GETOPT
1794 Answer Y if you want to include getopt_long[_only() used by many
1797 Most people will answer Y.
1799 config UCLIBC_HAS_GNU_GETSUBOPT
1800 bool "Support glibc getsubopt"
1803 Answer Y if you want to include glibc getsubopt() instead of a
1804 smaller SUSv3 compatible getsubopt().
1806 Most people will answer Y.
1812 config UCLIBC_HAS_REGEX
1813 bool "Regular Expression Support"
1816 POSIX regular expression code is really big -- 53k all by itself.
1817 If you don't use regular expressions, turn this off and save space.
1818 Of course, if you only statically link, leave this on, since it will
1819 only be included in your apps if you use regular expressions.
1821 config UCLIBC_HAS_REGEX_OLD
1822 bool "Use the older (stable) regular expression code"
1823 depends on UCLIBC_HAS_REGEX
1826 There are two versions of regex. The older (stable) version has
1827 been in uClibc for quite a long time but hasn't seen too many
1828 updates. It also has some known issues when dealing with uncommon
1829 corner cases and multibyte/unicode strings. However, it is quite
1830 a bit smaller than the newer version.
1832 If the older version has worked for you and you don't need unicode
1833 support, then stick with the old version (and say Y here).
1834 Otherwise, you should use the new version (and say N here).
1836 config UCLIBC_HAS_FNMATCH
1837 bool "fnmatch Support"
1842 config UCLIBC_HAS_FNMATCH_OLD
1843 bool "Use the older (stable) fnmatch code"
1844 depends on UCLIBC_HAS_FNMATCH
1847 There are two versions of fnmatch. The older (stable) version has
1848 been in uClibc for quite a long time but hasn't seen too many
1849 updates. It also has some known issues when dealing with uncommon
1850 corner cases and multibyte/unicode strings. However, it is quite
1851 a bit smaller than the newer version.
1853 If the older version has worked for you and you don't need unicode
1854 support, then stick with the old version (and say Y here).
1855 Otherwise, you should use the new version (and say N here).
1857 config UCLIBC_HAS_WORDEXP
1858 bool "Support the wordexp() interface"
1859 depends on UCLIBC_HAS_GLOB
1862 The SuSv3 wordexp() interface performs word expansions per the Shell
1863 and Utilities volume of IEEE Std 1003.1-2001, Section 2.6. It is
1864 intended for use by applications that want to implement all of the
1865 standard Bourne shell expansions on input data.
1867 This interface is rarely used, and very large. Unless you have a
1868 pressing need for wordexp(), you should probably answer N.
1870 config UCLIBC_HAS_NFTW
1871 bool "Support the nftw() interface"
1874 The SuSv3 nftw() interface is used to recursively descend
1875 directory paths while repeatedly calling a function.
1877 This interface is rarely used, and adds around 4.5k. Unless you have
1878 a pressing need for nftw(), you should probably answer N.
1880 config UCLIBC_HAS_FTW
1881 bool "Support the ftw() interface"
1883 depends on UCLIBC_SUSV4_LEGACY
1885 The SuSv3 ftw() interface is used to recursively descend
1886 directory paths while repeatedly calling a function.
1888 This interface is rarely used, and adds around 4.5k. Unless you have
1889 a pressing need for ftw(), you should probably answer N.
1892 config UCLIBC_HAS_GLOB
1893 bool "Support the glob() interface"
1894 depends on UCLIBC_HAS_FNMATCH
1898 The glob interface is somewhat large (weighing in at about 2,5k). It
1899 is used fairly often, but is an option since people wanting to go for
1900 absolute minimum size may wish to omit it.
1902 Most people will answer Y.
1904 config UCLIBC_HAS_GNU_GLOB
1905 bool "Support gnu glob() interface"
1906 depends on UCLIBC_HAS_GLOB
1909 The gnu glob interface is somewhat larger (weighing in at about 4,2k)
1910 than it's SuSv3 counterpart (and is out of date). It is an old copy
1911 from glibc and does not support all the GNU specific options.
1913 Answer Y if you want to include full gnu glob() instead of the smaller
1914 SUSv3 compatible glob().
1916 Most people will answer N.
1918 config UCLIBC_HAS_UTMPX
1919 bool "utmpx based support for tracking login/logouts to/from the system"
1922 Answer y to enable support for accessing user accounting database.
1923 It can be used to track all login/logout to the system.
1925 If unsure, just answer N.
1932 menu "Library Installation Options"
1934 config RUNTIME_PREFIX
1935 string "uClibc runtime library directory"
1936 default "/usr/$(TARGET_ARCH)-linux-uclibc/"
1938 RUNTIME_PREFIX is the directory into which the uClibc runtime
1939 libraries will be installed. The result will look something
1942 lib/ <contains all runtime libraries>
1943 usr/bin/ldd <the ldd utility program>
1944 sbin/ldconfig <the ldconfig utility program>
1945 This value is used by the 'make install' Makefile target. Since this
1946 directory is compiled into the shared library loader, you will need to
1947 recompile uClibc if you change this value...
1949 For a typical target system this should be set to "/", such that
1950 'make install' will install /lib/libuClibc-<VERSION>.so
1953 string "uClibc development environment directory"
1954 default "/usr/$(TARGET_ARCH)-linux-uclibc/usr/"
1956 DEVEL_PREFIX is the directory into which the uClibc development
1957 environment will be installed. The result will look something
1960 lib/ <contains static libs>
1961 include/ <Where all the header files go>
1962 This value is used by the 'make install' Makefile target when
1963 installing a uClibc development environment.
1965 For a typical target system this should be set to "/usr", such that
1966 'make install' will install /usr/include/<header files>.
1969 string "library path component"
1972 Path component where libraries reside.
1974 For a typical target system this should be set to "lib", such that
1975 'make install' will install libraries to "/lib" and "/usr/lib"
1977 DEVEL_PREFIX/MULTILIB_DIR
1978 RUNTIME_PREFIX/MULTILIB_DIR
1980 Other settings may include "lib32" or "lib64".
1982 config HARDWIRED_ABSPATH
1983 bool "Hardwire absolute paths into linker scripts"
1986 This prepends absolute paths to the libraries mentioned in linker
1987 scripts such as libc.so.
1989 This is a build time optimization. It has no impact on dynamic
1990 linking at runtime, which doesn't use linker scripts.
1992 You must disable this to use uClibc with old non-sysroot toolchains,
1993 such as the prebuilt binary cross compilers at:
1994 http://uclibc.org/downloads/binaries
1996 The amount of time saved by this optimization is actually too small to
1997 measure. The linker just had to search the library path to find the
1998 linker script, so the dentries are cache hot if it has to search the
1999 same path again. But it's what glibc does, so we do it too.
2004 menu "Security options"
2006 config UCLIBC_BUILD_PIE
2007 bool "Build utilities as ET_DYN/PIE executables"
2008 depends on HAVE_SHARED
2009 depends on TARGET_arm || TARGET_frv || TARGET_i386 || TARGET_mips || TARGET_powerpc
2010 select FORCE_SHAREABLE_TEXT_SEGMENTS
2013 If you answer Y here, ldd and iconv are built as ET_DYN/PIE
2016 It requires gcc-3.4 and binutils-2.15 (for arm 2.16) or later.
2017 More about ET_DYN/PIE binaries on <http://pax.grsecurity.net/> .
2019 WARNING: This option also enables FORCE_SHAREABLE_TEXT_SEGMENTS, so
2020 all libraries have to be built with -fPIC or -fpic, and all
2021 assembler functions must be written as position independent
2024 config UCLIBC_HAS_ARC4RANDOM
2025 bool "Include the arc4random() function"
2028 Answer Y to support the OpenBSD-like arc4random() function. This
2029 function picks a random number between 0 and N, and will always return
2030 something even if the random driver is dead. If urandom fails then
2031 gettimeofday(2) will be used as the random seed. This function is
2032 designed to be more dependable than invoking /dev/urandom directly.
2033 OpenSSL and OpenNTPD currently support this function.
2035 Most people will answer N.
2041 config UCLIBC_HAS_SSP
2042 bool "Support for GCC stack smashing protector"
2043 depends on !HAVE_NO_SSP
2046 Add code to support GCC's -fstack-protector[-all] option to uClibc.
2047 This requires GCC 4.1 or newer. GCC does not have to provide libssp,
2048 the needed functions are added to ldso/libc instead.
2050 GCC's stack protector is a reimplementation of IBM's propolice.
2051 See http://www.trl.ibm.com/projects/security/ssp/ and
2052 http://www.linuxfromscratch.org/hints/downloads/files/ssp.txt
2055 Note that NOEXECSTACK on a kernel with address space randomization
2056 is generally sufficient to prevent most buffer overflow exploits
2057 without increasing code size. This option essentially adds debugging
2060 Most people will answer N.
2062 config UCLIBC_HAS_SSP_COMPAT
2063 bool "Support for gcc-3.x propolice smashing stack protector"
2064 depends on UCLIBC_HAS_SSP
2067 Add gcc-3.x propolice smashing stack protector to the library.
2069 This requires a patched version of GCC, supporting the
2070 -fstack-protector[-all] options, with the __guard and
2071 __stack_smash_handler functions removed from libgcc.
2072 These functions are added to ldso/libc instead.
2074 More information at:
2075 <http://www.research.ibm.com/trl/projects/security/ssp/>
2077 Most people will answer N.
2079 config SSP_QUICK_CANARY
2080 bool "Use simple guard values without accessing /dev/urandom"
2081 depends on UCLIBC_HAS_SSP
2084 Use gettimeofday(2) to define the __guard without accessing
2086 WARNING: This makes smashing stack protector vulnerable to timing
2088 Most people will answer N.
2091 prompt "Propolice protection blocking signal"
2092 depends on UCLIBC_HAS_SSP
2093 default PROPOLICE_BLOCK_ABRT if ! DODEBUG
2094 default PROPOLICE_BLOCK_SEGV if DODEBUG
2096 "abort" use SIGABRT to block offending programs.
2097 This is the default implementation.
2099 "segfault" use SIGSEGV to block offending programs.
2100 Use this for debugging.
2102 If unsure, answer "abort".
2104 config PROPOLICE_BLOCK_ABRT
2107 config PROPOLICE_BLOCK_SEGV
2112 config UCLIBC_BUILD_SSP
2113 bool "Build uClibc with -fstack-protector"
2114 depends on UCLIBC_HAS_SSP
2117 Build all uClibc libraries and executables with -fstack-protector,
2118 adding extra stack overflow checking to most uClibc functions.
2120 config UCLIBC_BUILD_RELRO
2121 bool "Build uClibc with linker option -z RELRO"
2122 depends on HAVE_SHARED
2125 Build all libraries and executables with "ld -z relro".
2127 This tells the linker to mark chunks of an executable or shared
2128 library read-only after applying dynamic relocations. (This comes
2129 up when a global const variable is initialized to the address of a
2130 function or the value of another global variable.)
2132 This is a fairly obscure option the ld man page doesn't even bother
2133 to document properly. It's a security paranoia issue that's more
2134 likely to consume memory (by allocating an extra page) rather than
2137 This is explained in more depth at
2138 http://www.airs.com/blog/archives/189
2140 Nobody is likely to care whether you say Y or N here.
2142 config UCLIBC_BUILD_NOW
2143 bool "Build uClibc with linker option -z NOW"
2144 depends on HAVE_SHARED
2147 Build all libraries and executables with "ld -z now".
2149 This tells the linker to resolve all symbols when the library is
2150 first loaded, rather than when each function is first called. This
2151 increases start-up latency by a few microseconds and may do
2152 unnecessary work (resolving symbols that are never used), but the
2153 realtime people like it for making microbenchmark timings slightly
2154 more predictable and in some cases it can be slightly faster due to
2155 CPU cache behavior (not having to fault the linker back in to do
2156 lazy symbol resolution).
2158 Most people can't tell the difference between selecting Y or N here.
2160 config UCLIBC_BUILD_NOEXECSTACK
2161 bool "Build uClibc with noexecstack marking"
2164 Mark all assembler files as noexecstack, which will mark uClibc
2165 as not requiring an executable stack. (This doesn't prevent other
2166 files you link against from claiming to need an executable stack, it
2167 just won't cause uClibc to request it unnecessarily.)
2169 This is a security thing to make buffer overflows harder to exploit.
2170 By itself, it's kind of useless, as Linus Torvalds explained in 1998:
2171 http://old.lwn.net/1998/0806/a/linus-noexec.html
2173 It only actually provides any security when combined with address
2174 space randomization, explained here: http://lwn.net/Articles/121845/
2176 Address space randomization is on by default in current linux
2177 kernels (although it can be disabled using the option
2180 You should probably say Y.
2184 menu "uClibc development/debugging options"
2186 config CROSS_COMPILER_PREFIX
2187 string "Cross-compiling toolchain prefix"
2190 The prefix used to execute your cross-compiling toolchain. For
2191 example, if you run 'arm-linux-uclibc-gcc' to compile something,
2192 then enter 'arm-linux-uclibc-' here.
2194 config UCLIBC_EXTRA_CFLAGS
2195 string "Enter any extra CFLAGS to use to build uClibc"
2198 Add any additional CFLAGS to be used to build uClibc.
2201 bool "Build uClibc with debugging symbols"
2203 select EXTRA_WARNINGS
2205 Say Y here if you wish to compile uClibc with debugging symbols.
2206 This will allow you to use a debugger to examine uClibc internals
2207 while applications are running. This increases the size of the
2208 library considerably and should only be used when doing development.
2209 If you are doing development and want to debug uClibc, answer Y.
2211 Otherwise, answer N.
2214 bool "Build pthread with debugging output"
2215 depends on UCLIBC_HAS_THREADS && LINUXTHREADS_OLD
2218 Enable debug output in libpthread. This is only useful when doing
2219 development in libpthread itself.
2221 Otherwise, answer N.
2224 bool "Strip libraries and executables"
2228 Say Y here if you do wish to strip all uClibc libraries and
2229 executables. No stripping increases the size of the binaries
2230 considerably, but makes it possible to debug uClibc libraries.
2231 Most people will answer Y.
2234 bool "Build uClibc with run-time assertion testing"
2237 Say Y here to include runtime assertion tests.
2238 This enables runtime assertion testing in some code, which can
2239 increase the size of the library and incur runtime overhead.
2240 If you say N, then this testing will be disabled.
2242 config SUPPORT_LD_DEBUG
2243 bool "Build the shared library loader with debugging support"
2244 depends on HAVE_SHARED
2247 Answer Y here to enable all the extra code needed to debug the uClibc
2248 native shared library loader. The level of debugging noise that is
2249 generated depends on the LD_DEBUG environment variable... Just set
2250 LD_DEBUG to something like: 'LD_DEBUG=token1,token2,.. prog' to
2251 debug your application. Diagnostic messages will then be printed to
2254 For now these debugging tokens are available:
2255 detail provide more information for some options
2256 move display copy processing
2257 symbols display symbol table processing
2258 reloc display relocation processing; detail shows the
2260 nofixups never fixes up jump relocations
2261 bindings displays the resolve processing (function calls);
2262 detail shows the relocation patch
2263 all Enable everything!
2265 The additional environment variable:
2266 LD_DEBUG_OUTPUT=file
2267 redirects the diagnostics to an output file created using
2268 the specified name and the process id as a suffix.
2270 An excellent start is simply:
2271 $ LD_DEBUG=binding,move,symbols,reloc,detail ./appname
2272 or to log everything to a file named 'logfile', try this
2273 $ LD_DEBUG=all LD_DEBUG_OUTPUT=logfile ./appname
2275 If you are doing development and want to debug uClibc's shared library
2276 loader, answer Y. Mere mortals answer N.
2278 config SUPPORT_LD_DEBUG_EARLY
2279 bool "Build the shared library loader with early debugging support"
2280 depends on HAVE_SHARED
2283 Answer Y here to if you find the uClibc shared library loader is
2284 crashing or otherwise not working very early on. This is typical
2285 only when starting a new port when you haven't figured out how to
2286 properly get the values for argc, argv, environ, etc. This method
2287 allows a degree of visibility into the very early shared library
2288 loader initialization process. If you are doing development and want
2289 to debug the uClibc shared library loader early initialization,
2290 answer Y. Mere mortals answer N.
2292 config UCLIBC_MALLOC_DEBUGGING
2293 bool "Build malloc with debugging support"
2294 depends on MALLOC || MALLOC_STANDARD
2297 Answer Y here to compile extra debugging support code into malloc.
2298 Malloc debugging output may then be enabled at runtime using the
2299 MALLOC_DEBUG environment variable.
2301 The value of MALLOC_DEBUG should be an integer, which is interpreted
2302 as a bitmask with the following bits:
2303 1 - do extra consistency checking
2304 2 - output messages for malloc/free calls and OS
2306 4 - output messages for the `MMB' layer
2307 8 - output messages for internal malloc heap manipulation
2310 Because this increases the size of malloc appreciably (due to strings
2311 etc), you should say N unless you need to debug a malloc problem.
2313 config UCLIBC_HAS_BACKTRACE
2314 bool "Add support for application self-debugging"
2315 depends on HAVE_SHARED && TARGET_sh
2318 Answer Y here to compile support for application self-debugging, by adding
2319 a new shared object "libubacktrace.so" that provides the following new
2321 backtrace, backtrace_symbols, backtrace_symbols_fd
2323 The backtrace functionality is currently supported on SH platform, and it
2324 based on dwarf2 informations to properly work, so any application that
2325 want to use backtrace needs to be built with -fexceptions flag.
2327 The symbol names may be unavailable without the use of special linker
2328 options. For systems using the GNU linker, it is necessary to use the
2329 -rdynamic linker option too. Note that names of "static" functions are not
2330 exposed, and won't be available in the backtrace.
2333 string "Compiler Warnings"
2336 Set this to the set of gcc warnings you wish to see while compiling.
2338 config EXTRA_WARNINGS
2339 bool "Enable extra annoying warnings"
2342 If you wish to build with extra warnings enabled, say Y here.
2345 bool "Compile all sources at once into an object"
2348 Set this to compile all sources at once into an object (IMA).
2349 This mode of compilation uses alot of memory but may produce
2352 Note that you need a very recent GCC for this to work, like
2353 gcc >= 4.3 plus eventually some patches.
2355 If unsure, keep the default of N.
2357 config UCLIBC_MJN3_ONLY
2358 bool "Manuel's hidden warnings"
2361 Answer Y here to see all Manuel's personal notes, warnings, and todos.
2363 Most people will answer N.
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