macros/need-declaration.m4

   1 dnl See whether we need a declaration for a function.
   2 dnl GCC_NEED_DECLARATION(FUNCTION [, EXTRA-HEADER-FILES])
   3 AC_DEFUN([GCC_NEED_DECLARATION],
   4 [AC_MSG_CHECKING([whether $1 must be declared])
   5 AC_CACHE_VAL(gcc_cv_decl_needed_$1,
   6 [AC_TRY_COMPILE([
   7 #include <stdio.h>
   8 #ifdef HAVE_STRING_H
   9 #include <string.h>
  10 #else
  11 #ifdef HAVE_STRINGS_H
  12 #include <strings.h>
  13 #endif
  14 #endif
  15 #ifdef HAVE_STDLIB_H
  16 #include <stdlib.h>
  17 #endif
  18 #ifdef HAVE_UNISTD_H
  19 #include <unistd.h>
  20 #endif
  21 $2],
  22 [char *(*pfn) = (char *(*)) $1],
  23 eval "gcc_cv_decl_needed_$1=no", eval "gcc_cv_decl_needed_$1=yes")])
  24 if eval "test \"`echo '$gcc_cv_decl_needed_'$1`\" = yes"; then
  25   AC_MSG_RESULT(yes)
  26   gcc_need_declarations="$gcc_need_declarations $1"
  27   gcc_tr_decl=NEED_DECLARATION_`echo $1 | tr 'abcdefghijklmnopqrstuvwxyz' 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'`
  28   AC_DEFINE_UNQUOTED($gcc_tr_decl)
  29 else
  30   AC_MSG_RESULT(no)
  31 fi
  32 ])dnl
  33
  34 dnl Check multiple functions to see whether each needs a declaration.
  35 dnl GCC_NEED_DECLARATIONS(FUNCTION... [, EXTRA-HEADER-FILES])
  36 AC_DEFUN([GCC_NEED_DECLARATIONS],
  37 [for ac_func in $1
  38 do
  39 GCC_NEED_DECLARATION($ac_func, $2)
  40 done
  41 ]
  42 )