1# ffs.m4 serial 5 2dnl Copyright (C) 2011-2022 Free Software Foundation, Inc. 3dnl This file is free software; the Free Software Foundation 4dnl gives unlimited permission to copy and/or distribute it, 5dnl with or without modifications, as long as this notice is preserved. 6 7AC_DEFUN([gl_FUNC_FFS], 8[ 9 AC_REQUIRE([gl_STRINGS_H_DEFAULTS]) 10 11 dnl We can't use AC_CHECK_FUNC here, because ffs() is defined as a 12 dnl static inline function when compiling for Android 4.2 or older. 13 dnl But require that ffs() is declared; otherwise we may be using 14 dnl the GCC built-in function, which leads to warnings 15 dnl "warning: implicit declaration of function 'ffs'". 16 AC_CACHE_CHECK([for ffs], [gl_cv_func_ffs], 17 [AC_LINK_IFELSE( 18 [AC_LANG_PROGRAM( 19 [[#include <strings.h> 20 int x; 21 ]], 22 [[int (*func) (int) = ffs; 23 return func (x); 24 ]]) 25 ], 26 [gl_cv_func_ffs=yes], 27 [gl_cv_func_ffs=no]) 28 ]) 29 if test $gl_cv_func_ffs = no; then 30 HAVE_FFS=0 31 fi 32]) 33