use _GL_ATTRIBUTE_CONST and _GL_ATTRIBUTE_PURE

[gnulib.git] / lib / memchr2.c

diff --git a/lib/memchr2.c b/lib/memchr2.c
index 2e3c7cd..b830b9d 100644 (file)
--- a/lib/memchr2.c
+++ b/lib/memchr2.c
@@ -29,10 +29,18 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <stdint.h>
 #include <string.h>
 
+/* The attribute __pure__ was added in gcc 2.96.  */
+#undef _GL_ATTRIBUTE_PURE
+#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 96)
+# define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__))
+#else
+# define _GL_ATTRIBUTE_PURE /* empty */
+#endif
+
 /* Return the first address of either C1 or C2 (treated as unsigned
    char) that occurs within N bytes of the memory region S.  If
    neither byte appears, return NULL.  */
-void *
+void * _GL_ATTRIBUTE_PURE
 memchr2 (void const *s, int c1_in, int c2_in, size_t n)
 {
   /* On 32-bit hardware, choosing longword to be a 32-bit unsigned