diff options
Diffstat (limited to 'gl/m4/memchr.m4')
| -rw-r--r-- | gl/m4/memchr.m4 | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/gl/m4/memchr.m4 b/gl/m4/memchr.m4 index ab773b81..2d8abe75 100644 --- a/gl/m4/memchr.m4 +++ b/gl/m4/memchr.m4 @@ -1,5 +1,5 @@ -# memchr.m4 serial 8 -dnl Copyright (C) 2002-2004, 2009-2010 Free Software Foundation, Inc. +# memchr.m4 serial 12 +dnl Copyright (C) 2002-2004, 2009-2013 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. @@ -11,10 +11,16 @@ AC_DEFUN_ONCE([gl_FUNC_MEMCHR], AC_CHECK_HEADERS_ONCE([sys/mman.h]) AC_CHECK_FUNCS_ONCE([mprotect]) - dnl These days, we assume memchr is present. But just in case... AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS]) - AC_CHECK_FUNCS_ONCE([memchr]) - if test $ac_cv_func_memchr = yes; then + m4_ifdef([gl_FUNC_MEMCHR_OBSOLETE], [ + dnl These days, we assume memchr is present. But if support for old + dnl platforms is desired: + AC_CHECK_FUNCS_ONCE([memchr]) + if test $ac_cv_func_memchr = no; then + HAVE_MEMCHR=0 + fi + ]) + if test $HAVE_MEMCHR = 1; then # Detect platform-specific bugs in some versions of glibc: # memchr should not dereference anything with length 0 # http://bugzilla.redhat.com/499689 @@ -35,6 +41,7 @@ AC_DEFUN_ONCE([gl_FUNC_MEMCHR], # endif #endif ]], [[ + int result = 0; char *fence = NULL; #if HAVE_SYS_MMAN_H && HAVE_MPROTECT # if HAVE_MAP_ANONYMOUS @@ -58,24 +65,20 @@ AC_DEFUN_ONCE([gl_FUNC_MEMCHR], if (fence) { if (memchr (fence, 0, 0)) - return 1; + result |= 1; strcpy (fence - 9, "12345678"); if (memchr (fence - 9, 0, 79) != fence - 1) - return 2; + result |= 2; + if (memchr (fence - 1, 0, 3) != fence - 1) + result |= 4; } - return 0; + return result; ]])], [gl_cv_func_memchr_works=yes], [gl_cv_func_memchr_works=no], [dnl Be pessimistic for now. gl_cv_func_memchr_works="guessing no"])]) if test "$gl_cv_func_memchr_works" != yes; then REPLACE_MEMCHR=1 fi - else - HAVE_MEMCHR=0 - fi - if test $HAVE_MEMCHR = 0 || test $REPLACE_MEMCHR = 1; then - AC_LIBOBJ([memchr]) - gl_PREREQ_MEMCHR fi ]) |