X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fftello.m4;h=10cf4291bfa7fc9aea68b7d94b5f2076e84ef39e;hb=d21602db7c1b97cd12478c3e40355ccb39556068;hp=225e9859566cd22b085c4e489b6002821fc145f5;hpb=7bfa0dd93fb4adf45f062ae29aa06a3d95655f45;p=gnulib.git

diff --git a/m4/ftello.m4 b/m4/ftello.m4
index 225e98595..10cf4291b 100644
--- a/m4/ftello.m4
+++ b/m4/ftello.m4
@@ -1,5 +1,5 @@
-# ftello.m4 serial 5
-dnl Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
+# ftello.m4 serial 10
+dnl Copyright (C) 2007-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -10,23 +10,118 @@ AC_DEFUN([gl_FUNC_FTELLO],
   AC_REQUIRE([AC_PROG_CC])
   AC_REQUIRE([gl_STDIN_LARGE_OFFSET])
 
-  dnl Persuade glibc <stdio.h> to declare fseeko().
+  dnl Persuade glibc <stdio.h> to declare ftello().
   AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
+  AC_CHECK_DECLS_ONCE([ftello])
+  if test $ac_cv_have_decl_ftello = no; then
+    HAVE_DECL_FTELLO=0
+  fi
+
   AC_CACHE_CHECK([for ftello], [gl_cv_func_ftello],
     [
-      AC_TRY_LINK([#include <stdio.h>], [ftello (stdin);],
-        [gl_cv_func_ftello=yes], [gl_cv_func_ftello=no])
+      AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#include <stdio.h>]],
+           [[ftello (stdin);]])],
+        [gl_cv_func_ftello=yes],
+        [gl_cv_func_ftello=no])
     ])
-  if test $gl_cv_func_ftello = no \
-      || test $gl_cv_var_stdin_large_offset = no; then
-    gl_REPLACE_FTELLO
-  fi
-])
+  if test $gl_cv_func_ftello = no; then
+    HAVE_FTELLO=0
+  else
+    if test $gl_cv_var_stdin_large_offset = no; then
+      REPLACE_FTELLO=1
+    else
+      dnl Detect bug on Solaris.
+      dnl ftell and ftello produce incorrect results after putc that followed a
+      dnl getc call that reached EOF on Solaris. This is because the _IOREAD
+      dnl flag does not get cleared in this case, even though _IOWRT gets set,
+      dnl and ftell and ftello look whether the _IOREAD flag is set.
+      AC_REQUIRE([AC_CANONICAL_HOST])
+      AC_CACHE_CHECK([whether ftello works],
+        [gl_cv_func_ftello_works],
+        [
+          dnl Initial guess, used when cross-compiling or when /dev/tty cannot
+          dnl be opened.
+changequote(,)dnl
+          case "$host_os" in
+                      # Guess no on Solaris.
+            solaris*) gl_cv_func_ftello_works="guessing no" ;;
+                      # Guess yes otherwise.
+            *)        gl_cv_func_ftello_works="guessing yes" ;;
+          esac
+changequote([,])dnl
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#define TESTFILE "conftest.tmp"
+int
+main (void)
+{
+  FILE *fp;
 
-AC_DEFUN([gl_REPLACE_FTELLO],
-[
-  AC_LIBOBJ([ftello])
-  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
-  REPLACE_FTELLO=1
+  /* Create a file with some contents.  */
+  fp = fopen (TESTFILE, "w");
+  if (fp == NULL)
+    return 70;
+  if (fwrite ("foogarsh", 1, 8, fp) < 8)
+    return 71;
+  if (fclose (fp))
+    return 72;
+
+  /* The file's contents is now "foogarsh".  */
+
+  /* Try writing after reading to EOF.  */
+  fp = fopen (TESTFILE, "r+");
+  if (fp == NULL)
+    return 73;
+  if (fseek (fp, -1, SEEK_END))
+    return 74;
+  if (!(getc (fp) == 'h'))
+    return 1;
+  if (!(getc (fp) == EOF))
+    return 2;
+  if (!(ftell (fp) == 8))
+    return 3;
+  if (!(ftell (fp) == 8))
+    return 4;
+  if (!(putc ('!', fp) == '!'))
+    return 5;
+  if (!(ftell (fp) == 9))
+    return 6;
+  if (!(fclose (fp) == 0))
+    return 7;
+  fp = fopen (TESTFILE, "r");
+  if (fp == NULL)
+    return 75;
+  {
+    char buf[10];
+    if (!(fread (buf, 1, 10, fp) == 9))
+      return 10;
+    if (!(memcmp (buf, "foogarsh!", 9) == 0))
+      return 11;
+  }
+  if (!(fclose (fp) == 0))
+    return 12;
+
+  /* The file's contents is now "foogarsh!".  */
+
+  return 0;
+}]])],
+            [gl_cv_func_ftello_works=yes],
+            [gl_cv_func_ftello_works=no], [:])
+        ])
+      case "$gl_cv_func_ftello_works" in
+        *yes) ;;
+        *)
+          REPLACE_FTELLO=1
+          AC_DEFINE([FTELLO_BROKEN_AFTER_SWITCHING_FROM_READ_TO_WRITE], [1],
+            [Define to 1 if the system's ftello function has the Solaris bug.])
+          ;;
+      esac
+    fi
+  fi
 ])