+/*******************************************************************************
+ * IMPLEMENTATION OPTIONS
+ *******************************************************************************
+ *
+ * Support for arbitrary implementation-specific optimizations. The API allows
+ * particular options to be turned on or off. 'Option' is the number of the
+ * option and 'onoff' is 0 (off) or non-0 (on). The value returned is given
+ * by the PNG_OPTION_ defines below.
+ *
+ * HARDWARE: normally hardware capabilites, such as the Intel SSE instructions,
+ * are detected at run time, however sometimes it may be impossible
+ * to do this in user mode, in which case it is necessary to discover
+ * the capabilities in an OS specific way. Such capabilities are
+ * listed here when libpng has support for them and must be turned
+ * ON by the application if present.
+ *
+ * SOFTWARE: sometimes software optimizations actually result in performance
+ * decrease on some architectures or systems, or with some sets of
+ * PNG images. 'Software' options allow such optimizations to be
+ * selected at run time.
+ */
+#ifdef PNG_SET_OPTION_SUPPORTED
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+# define PNG_ARM_NEON 0 /* HARDWARE: ARM Neon SIMD instructions supported */
+#endif
+#define PNG_OPTION_NEXT 2 /* Next option - numbers must be even */
+
+/* Return values: NOTE: there are four values and 'off' is *not* zero */
+#define PNG_OPTION_UNSET 0 /* Unset - defaults to off */
+#define PNG_OPTION_INVALID 1 /* Option number out of range */
+#define PNG_OPTION_OFF 2
+#define PNG_OPTION_ON 3
+
+PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
+ int onoff));
+#endif
+
+/*******************************************************************************
+ * END OF HARDWARE OPTIONS
+ ******************************************************************************/
+