X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Ffflush.m4;h=d8069c9122119347212321053b00c6ff85a3c547;hb=1276a2c5f24c0c932426aca9c899fa524d2443f2;hp=97f12843d4f1f111580cf616d0ac1b6afed3c0ef;hpb=02a3c7672c7d677774cf01038f57ab00d73b42d2;p=gnulib.git

diff --git a/m4/fflush.m4 b/m4/fflush.m4
index 97f12843d..d8069c912 100644
--- a/m4/fflush.m4
+++ b/m4/fflush.m4
@@ -1,6 +1,6 @@
-# fflush.m4 serial 6
+# fflush.m4 serial 15
 
-# Copyright (C) 2007-2008 Free Software Foundation, Inc.
+# Copyright (C) 2007-2014 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.
@@ -12,56 +12,78 @@ dnl unread input on seekable streams, rather than C99 undefined semantics.
 
 AC_DEFUN([gl_FUNC_FFLUSH],
 [
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  gl_FUNC_FFLUSH_STDIN
+  if test $gl_cv_func_fflush_stdin != yes; then
+    REPLACE_FFLUSH=1
+  fi
+])
+
+dnl Determine whether fflush works on input streams.
+dnl Sets gl_cv_func_fflush_stdin.
+
+AC_DEFUN([gl_FUNC_FFLUSH_STDIN],
+[
+  AC_CHECK_HEADERS_ONCE([unistd.h])
   AC_CACHE_CHECK([whether fflush works on input streams],
     [gl_cv_func_fflush_stdin],
     [echo hello world > conftest.txt
      AC_RUN_IFELSE([AC_LANG_PROGRAM(
        [[
 #include <stdio.h>
-#include <unistd.h>
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#else /* on Windows with MSVC */
+# include <io.h>
+#endif
        ]], [[FILE *f = fopen ("conftest.txt", "r");
-	 char buffer[10];
-	 int fd;
-	 if (f == NULL)
-	   return 1;
-	 fd = fileno (f);
-	 if (fd < 0 || fread (buffer, 1, 5, f) != 5)
-	   return 2;
-	 /* For deterministic results, ensure f read a bigger buffer.  */
-	 if (lseek (fd, 0, SEEK_CUR) == 5)
-	   return 3;
-	 /* POSIX requires fflush-fseek to set file offset of fd.  */
-	 if (fflush (f) != 0 || fseek (f, 0, SEEK_CUR) != 0)
-	   return 4;
-	 if (lseek (fd, 0, SEEK_CUR) != 5)
-	   return 5;
-	 /* TODO: Verify behaviour of fflush after ungetc, see
-	    <http://lists.gnu.org/archive/html/bug-gnulib/2008-03/msg00131.html>.  */
-	 return 0;
+         char buffer[10];
+         int fd;
+         int c;
+         if (f == NULL)
+           return 1;
+         fd = fileno (f);
+         if (fd < 0 || fread (buffer, 1, 5, f) != 5)
+           return 2;
+         /* For deterministic results, ensure f read a bigger buffer.  */
+         if (lseek (fd, 0, SEEK_CUR) == 5)
+           return 3;
+         /* POSIX requires fflush-fseek to set file offset of fd.  This fails
+            on BSD systems and on mingw.  */
+         if (fflush (f) != 0 || fseek (f, 0, SEEK_CUR) != 0)
+           return 4;
+         if (lseek (fd, 0, SEEK_CUR) != 5)
+           return 5;
+         /* Verify behaviour of fflush after ungetc. See
+            <http://www.opengroup.org/austin/aardvark/latest/xshbug3.txt>  */
+         /* Verify behaviour of fflush after a backup ungetc.  This fails on
+            mingw.  */
+         c = fgetc (f);
+         ungetc (c, f);
+         fflush (f);
+         if (fgetc (f) != c)
+           return 6;
+         /* Verify behaviour of fflush after a non-backup ungetc.  This fails
+            on glibc 2.8 and on BSD systems.  */
+         c = fgetc (f);
+         ungetc ('@', f);
+         fflush (f);
+         if (fgetc (f) != c)
+           return 7;
+         return 0;
        ]])], [gl_cv_func_fflush_stdin=yes], [gl_cv_func_fflush_stdin=no],
-     [dnl Pessimistically assume fflush is broken.  This is wrong for
-      dnl at least glibc and cygwin; but lib/fflush.c takes this into account.
-      gl_cv_func_fflush_stdin=no])
+     [gl_cv_func_fflush_stdin=cross])
      rm conftest.txt
     ])
-  if test $gl_cv_func_fflush_stdin = no; then
-    gl_REPLACE_FFLUSH
-  fi
-])
-
-AC_DEFUN([gl_REPLACE_FFLUSH],
-[
-  AC_LIBOBJ([fflush])
-  AC_LIBOBJ([fseeko])
-  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
-  REPLACE_FFLUSH=1
-  REPLACE_FSEEKO=1
-  gl_PREREQ_FFLUSH
+  case $gl_cv_func_fflush_stdin in
+    yes) gl_func_fflush_stdin=1 ;;
+    no)  gl_func_fflush_stdin=0 ;;
+    *)   gl_func_fflush_stdin='(-1)' ;;
+  esac
+  AC_DEFINE_UNQUOTED([FUNC_FFLUSH_STDIN], [$gl_func_fflush_stdin],
+    [Define to 1 if fflush is known to work on stdin as per POSIX.1-2008,
+     0 if fflush is known to not work, -1 if unknown.])
 ])
 
 # Prerequisites of lib/fflush.c.
-AC_DEFUN([gl_PREREQ_FFLUSH],
-[
-  AC_REQUIRE([AC_C_INLINE])
-  :
-])
+AC_DEFUN([gl_PREREQ_FFLUSH], [:])