GCC_NEED_DECLARATION used to prevent (maintainer-only) GCC warnings.

[mdsms.git] / need-declaration.m4

diff --git a/need-declaration.m4 b/need-declaration.m4
new file mode 100644 (file)
index 0000000..d5b7bc6
--- /dev/null
+++ b/need-declaration.m4
@@ -0,0 +1,42 @@
+dnl See whether we need a declaration for a function.
+dnl GCC_NEED_DECLARATION(FUNCTION [, EXTRA-HEADER-FILES])
+AC_DEFUN(GCC_NEED_DECLARATION,
+[AC_MSG_CHECKING([whether $1 must be declared])
+AC_CACHE_VAL(gcc_cv_decl_needed_$1,
+[AC_TRY_COMPILE([
+#include <stdio.h>
+#ifdef HAVE_STRING_H
+#include <string.h>
+#else
+#ifdef HAVE_STRINGS_H
+#include <strings.h>
+#endif
+#endif
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+$2],
+[char *(*pfn) = (char *(*)) $1],
+eval "gcc_cv_decl_needed_$1=no", eval "gcc_cv_decl_needed_$1=yes")])
+if eval "test \"`echo '$gcc_cv_decl_needed_'$1`\" = yes"; then
+  AC_MSG_RESULT(yes)
+  gcc_need_declarations="$gcc_need_declarations $1"
+  gcc_tr_decl=NEED_DECLARATION_`echo $1 | tr 'abcdefghijklmnopqrstuvwxyz' 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'`
+  AC_DEFINE_UNQUOTED($gcc_tr_decl)
+else
+  AC_MSG_RESULT(no)
+fi
+])dnl
+
+dnl Check multiple functions to see whether each needs a declaration.
+dnl GCC_NEED_DECLARATIONS(FUNCTION... [, EXTRA-HEADER-FILES])
+AC_DEFUN(GCC_NEED_DECLARATIONS,
+[for ac_func in $1
+do
+GCC_NEED_DECLARATION($ac_func, $2)
+done
+]
+)