Albert Chin's patch posted to the mailing list 19 Apr 2001

acinclude.m4

-#serial 12
+#serial 19
 
 dnl By default, many hosts won't let programs access large files;
 dnl one must use special compiler options to get large-file access to work.
@@ -11,7 +11,14 @@ dnl Internal subroutine of AC_SYS_LARGEFILE.
 dnl AC_SYS_LARGEFILE_TEST_INCLUDES
 AC_DEFUN(AC_SYS_LARGEFILE_TEST_INCLUDES,
   [[#include <sys/types.h>
-    int a[(off_t) 9223372036854775807 == 9223372036854775807 ? 1 : -1];
+    /* Check that off_t can represent 2**63 - 1 correctly.
+       We can't simply "#define LARGE_OFF_T 9223372036854775807",
+       since some C++ compilers masquerading as C compilers
+       incorrectly reject 9223372036854775807.  */
+#   define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
+    int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
+			&& LARGE_OFF_T % 2147483647 == 1)
+		       ? 1 : -1];
   ]])
 
 dnl Internal subroutine of AC_SYS_LARGEFILE.
@@ -19,14 +26,11 @@ dnl AC_SYS_LARGEFILE_MACRO_VALUE(C-MACRO, VALUE, CACHE-VAR, COMMENT, INCLUDES, F
 AC_DEFUN(AC_SYS_LARGEFILE_MACRO_VALUE,
   [AC_CACHE_CHECK([for $1 value needed for large files], $3,
      [$3=no
-      AC_TRY_COMPILE(AC_SYS_LARGEFILE_TEST_INCLUDES
-$5
-        ,
+      AC_TRY_COMPILE([$5],
 	[$6], 
 	,
 	[AC_TRY_COMPILE([#define $1 $2]
-AC_SYS_LARGEFILE_TEST_INCLUDES
-$5
+[$5]
 	   ,
 	   [$6],
 	   [$3=$2])])])
@@ -35,7 +39,8 @@ $5
    fi])
 
 AC_DEFUN(AC_SYS_LARGEFILE,
-  [AC_ARG_ENABLE(largefile,
+  [AC_REQUIRE([AC_PROG_CC])
+   AC_ARG_ENABLE(largefile,
      [  --disable-largefile     omit support for large files])
    if test "$enable_largefile" != no; then
 
@@ -58,18 +63,30 @@ AC_DEFUN(AC_SYS_LARGEFILE,
 
      AC_SYS_LARGEFILE_MACRO_VALUE(_FILE_OFFSET_BITS, 64,
        ac_cv_sys_file_offset_bits,
-       [Number of bits in a file offset, on hosts where this is settable.])
-     AC_SYS_LARGEFILE_MACRO_VALUE(_LARGEFILE_SOURCE, 1,
-       ac_cv_sys_largefile_source,
-       [Define to make ftello visible on some hosts (e.g. HP-UX 10.20).],
-       [#include <stdio.h>], [return !ftello;])
+       [Number of bits in a file offset, on hosts where this is settable.],
+       AC_SYS_LARGEFILE_TEST_INCLUDES)
      AC_SYS_LARGEFILE_MACRO_VALUE(_LARGE_FILES, 1,
        ac_cv_sys_large_files,
-       [Define for large files, on AIX-style hosts.])
-dnl	lftp does not need ftello, and _XOPEN_SOURCE=500 makes resolv.h fail.
-dnl     AC_SYS_LARGEFILE_MACRO_VALUE(_XOPEN_SOURCE, 500,
-dnl       ac_cv_sys_xopen_source,
-dnl       [Define to make ftello visible on some hosts (e.g. glibc 2.1.3).],
-dnl       [#include <stdio.h>], [return !ftello;])
+       [Define for large files, on AIX-style hosts.],
+       AC_SYS_LARGEFILE_TEST_INCLUDES)
    fi
   ])
+
+AC_DEFUN(AC_FUNC_FSEEKO,
+  [AC_SYS_LARGEFILE_MACRO_VALUE(_LARGEFILE_SOURCE, 1,
+     ac_cv_sys_largefile_source,
+     [Define to make fseeko visible on some hosts (e.g. glibc 2.2).],
+     [#include <stdio.h>], [return !fseeko;])
+   # We used to try defining _XOPEN_SOURCE=500 too, to work around a bug
+   # in glibc 2.1.3, but that breaks too many other things.
+   # If you want fseeko and ftello with glibc, upgrade to a fixed glibc.
+
+   AC_CACHE_CHECK([for fseeko], ac_cv_func_fseeko,
+     [ac_cv_func_fseeko=no
+      AC_TRY_LINK([#include <stdio.h>],
+        [return fseeko && fseeko (stdin, 0, 0);],
+	[ac_cv_func_fseeko=yes])])
+   if test $ac_cv_func_fseeko != no; then
+     AC_DEFINE(HAVE_FSEEKO, 1,
+       [Define if fseeko (and presumably ftello) exists and is declared.])
+   fi])