getopt-gnu: suppress core dumps from detection code
[gnulib.git] / m4 / fpending.m4
index d086ac6..5d93f8e 100644 (file)
@@ -1,4 +1,9 @@
-#serial 4
+# serial 16
+
+# Copyright (C) 2000-2001, 2004-2011 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
 
 dnl From Jim Meyering
 dnl Using code from emacs, based on suggestions from Paul Eggert
 
 dnl From Jim Meyering
 dnl Using code from emacs, based on suggestions from Paul Eggert
@@ -10,63 +15,70 @@ dnl we have to grub around in the FILE struct.
 
 AC_DEFUN([gl_FUNC_FPENDING],
 [
 
 AC_DEFUN([gl_FUNC_FPENDING],
 [
-  AC_CHECK_HEADERS(stdio_ext.h)
-  AC_REPLACE_FUNCS([__fpending])
+  AC_CHECK_HEADERS_ONCE([stdio_ext.h])
+  AC_CHECK_FUNCS_ONCE([__fpending])
   fp_headers='
   fp_headers='
+#     include <stdio.h>
 #     if HAVE_STDIO_EXT_H
 #      include <stdio_ext.h>
 #     endif
 '
   AC_CHECK_DECLS([__fpending], , , $fp_headers)
 #     if HAVE_STDIO_EXT_H
 #      include <stdio_ext.h>
 #     endif
 '
   AC_CHECK_DECLS([__fpending], , , $fp_headers)
-  if test $ac_cv_func___fpending = no; then
-    AC_CACHE_CHECK(
-             [how to determine the number of pending output bytes on a stream],
-                  ac_cv_sys_pending_output_n_bytes,
-      [
-       for ac_expr in                                          \
-                                                               \
-           '# glibc2'                                          \
-           'fp->_IO_write_ptr - fp->_IO_write_base'            \
-                                                               \
-           '# traditional Unix'                                \
-           'fp->_ptr - fp->_base'                              \
-                                                               \
-           '# BSD'                                             \
-           'fp->_p - fp->_bf._base'                            \
-                                                               \
-           '# SCO, Unixware'                                   \
-           'fp->__ptr - fp->__base'                            \
-                                                               \
-           '# old glibc?'                                      \
-           'fp->__bufp - fp->__buffer'                         \
-                                                               \
-           '# old glibc iostream?'                             \
-           'fp->_pptr - fp->_pbase'                            \
-                                                               \
-           '# VMS'                                             \
-           '(*fp)->_ptr - (*fp)->_base'                        \
-                                                               \
-           '# e.g., DGUX R4.11; the info is not available'     \
-           1                                                   \
-           ; do
+])
+
+AC_DEFUN([gl_PREREQ_FPENDING],
+[
+  AC_CACHE_CHECK(
+              [how to determine the number of pending output bytes on a stream],
+                 ac_cv_sys_pending_output_n_bytes,
+    [
+      for ac_expr in                                                    \
+                                                                        \
+          '# glibc2'                                                    \
+          'fp->_IO_write_ptr - fp->_IO_write_base'                      \
+                                                                        \
+          '# traditional Unix'                                          \
+          'fp->_ptr - fp->_base'                                        \
+                                                                        \
+          '# BSD'                                                       \
+          'fp->_p - fp->_bf._base'                                      \
+                                                                        \
+          '# SCO, Unixware'                                             \
+          '(fp->__ptr ? fp->__ptr - fp->__base : 0)'                    \
+                                                                        \
+          '# QNX'                                                       \
+          '(fp->_Mode & 0x2000 /*_MWRITE*/ ? fp->_Next - fp->_Buf : 0)' \
+                                                                        \
+          '# old glibc?'                                                \
+          'fp->__bufp - fp->__buffer'                                   \
+                                                                        \
+          '# old glibc iostream?'                                       \
+          'fp->_pptr - fp->_pbase'                                      \
+                                                                        \
+          '# emx+gcc'                                                   \
+          'fp->_ptr - fp->_buffer'                                      \
+                                                                        \
+          '# VMS'                                                       \
+          '(*fp)->_ptr - (*fp)->_base'                                  \
+                                                                        \
+          '# e.g., DGUX R4.11; the info is not available'               \
+          1                                                             \
+          ; do
 
 
-         # Skip each embedded comment.
-         case "$ac_expr" in '#'*) continue;; esac
+        # Skip each embedded comment.
+        case "$ac_expr" in '#'*) continue;; esac
 
 
-         AC_TRY_COMPILE(
-           [#include <stdio.h>
-           ],
-           [FILE *fp = stdin; (void) ($ac_expr);],
-           fp_done=yes
-         )
-         test "$fp_done" = yes && break
-       done
+        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>]],
+          [[FILE *fp = stdin; (void) ($ac_expr);]])],
+          [fp_done=yes]
+        )
+        test "$fp_done" = yes && break
+      done
 
 
-       ac_cv_sys_pending_output_n_bytes=$ac_expr
-      ]
-    )
-    AC_DEFINE_UNQUOTED(PENDING_OUTPUT_N_BYTES,
-      $ac_cv_sys_pending_output_n_bytes,
-      [the number of pending output bytes on stream `fp'])
-  fi
+      ac_cv_sys_pending_output_n_bytes=$ac_expr
+    ]
+  )
+  AC_DEFINE_UNQUOTED([PENDING_OUTPUT_N_BYTES],
+    $ac_cv_sys_pending_output_n_bytes,
+    [the number of pending output bytes on stream `fp'])
 ])
 ])