Paul Eggert wrote:
> * doc/posix-headers/limits.texi (limits.h): Document this.
> * lib/limits.in.h (SSIZE_MAX): Define if not already defined.
When I add a unit test for this, I see that the assertion
static_assert (TYPE_MAXIMUM (ssize_t) == SSIZE_MAX);
fails on 64-bit MSVC 14. That's because on this platform, gnulib
defines ssize_t as 'int', i.e. 32-bit, whereas size_t is 64-bit.
Ouch. And when we used
# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
that value actually was (int)(-1). Ouch ouch.
2023-05-21 Bruno Haible <br...@clisp.org>
limits-h tests: Check the value of SSIZE_MAX.
* tests/test-limits-h.c (limits12): New variable.
Include <sys/types.h> and check the value of SSIZE_MAX.
* modules/limits-h-tests (Depends-on): Add sys_types.
2023-05-21 Bruno Haible <br...@clisp.org>
ssize_t: Fix replacement on 64-bit Windows.
* m4/ssize_t.m4 (gt_TYPE_SSIZE_T): Use prefix 'gl_' instead of 'gt_'.
Define ssize_t to 'long long' or 'long', depending on the width of
'size_t'.
>From 138b4121298c14e1fd6ca751ab557a1d65443f01 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Sun, 21 May 2023 14:40:04 +0200
Subject: [PATCH 1/2] ssize_t: Fix replacement on 64-bit Windows.
* m4/ssize_t.m4 (gt_TYPE_SSIZE_T): Use prefix 'gl_' instead of 'gt_'.
Define ssize_t to 'long long' or 'long', depending on the width of
'size_t'.
---
ChangeLog | 7 +++++++
m4/ssize_t.m4 | 28 +++++++++++++++++++++-------
2 files changed, 28 insertions(+), 7 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 7253bd7ea3..e205c02f43 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2023-05-21 Bruno Haible <br...@clisp.org>
+
+ ssize_t: Fix replacement on 64-bit Windows.
+ * m4/ssize_t.m4 (gt_TYPE_SSIZE_T): Use prefix 'gl_' instead of 'gt_'.
+ Define ssize_t to 'long long' or 'long', depending on the width of
+ 'size_t'.
+
2023-05-20 Paul Eggert <egg...@cs.ucla.edu>
limits-h: other modules can rely on SSIZE_MAX
diff --git a/m4/ssize_t.m4 b/m4/ssize_t.m4
index 1c12c33ea0..52bd77d2ae 100644
--- a/m4/ssize_t.m4
+++ b/m4/ssize_t.m4
@@ -1,23 +1,37 @@
-# ssize_t.m4 serial 5 (gettext-0.18.2)
+# ssize_t.m4 serial 6
dnl Copyright (C) 2001-2003, 2006, 2010-2023 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.
dnl From Bruno Haible.
-dnl Test whether ssize_t is defined.
+dnl Define ssize_t if it does not already exist.
AC_DEFUN([gt_TYPE_SSIZE_T],
[
- AC_CACHE_CHECK([for ssize_t], [gt_cv_ssize_t],
+ AC_CACHE_CHECK([for ssize_t], [gl_cv_ssize_t],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[#include <sys/types.h>]],
[[int x = sizeof (ssize_t *) + sizeof (ssize_t);
return !x;]])],
- [gt_cv_ssize_t=yes], [gt_cv_ssize_t=no])])
- if test $gt_cv_ssize_t = no; then
- AC_DEFINE([ssize_t], [int],
- [Define as a signed type of the same size as size_t.])
+ [gl_cv_ssize_t=yes], [gl_cv_ssize_t=no])])
+ if test $gl_cv_ssize_t = no; then
+ dnl On 64-bit native Windows, ssize_t needs to be defined as 'long long',
+ dnl for consistency with the 64-bit size_t.
+ AC_CACHE_CHECK([whether size_t is wider than 'long'], [gl_cv_size_t_large],
+ [AC_COMPILE_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <sys/types.h>
+ typedef int array [2 * (sizeof (size_t) > sizeof (long)) - 1];
+ ]])],
+ [gl_cv_size_t_large=yes], [gl_cv_size_t_large=no])])
+ if test $gl_cv_size_t_large = yes; then
+ gl_def_ssize_t='long long'
+ else
+ gl_def_ssize_t='long'
+ fi
+ AC_DEFINE_UNQUOTED([ssize_t], [$gl_def_ssize_t],
+ [Define as a signed type of the same size as size_t.])
fi
])
--
2.34.1
>From a5865b6ed2fe6810ec1f557e79794ce525fcb935 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Sun, 21 May 2023 14:42:27 +0200
Subject: [PATCH 2/2] limits-h tests: Check the value of SSIZE_MAX.
* tests/test-limits-h.c (limits12): New variable.
Include <sys/types.h> and check the value of SSIZE_MAX.
* modules/limits-h-tests (Depends-on): Add sys_types.
---
ChangeLog | 7 +++++++
modules/limits-h-tests | 1 +
tests/test-limits-h.c | 11 +++++++++++
3 files changed, 19 insertions(+)
diff --git a/ChangeLog b/ChangeLog
index e205c02f43..9cdb603b9b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2023-05-21 Bruno Haible <br...@clisp.org>
+
+ limits-h tests: Check the value of SSIZE_MAX.
+ * tests/test-limits-h.c (limits12): New variable.
+ Include <sys/types.h> and check the value of SSIZE_MAX.
+ * modules/limits-h-tests (Depends-on): Add sys_types.
+
2023-05-21 Bruno Haible <br...@clisp.org>
ssize_t: Fix replacement on 64-bit Windows.
diff --git a/modules/limits-h-tests b/modules/limits-h-tests
index 2cf0a41f5d..51919ad1a1 100644
--- a/modules/limits-h-tests
+++ b/modules/limits-h-tests
@@ -4,6 +4,7 @@ tests/test-limits-h.c
Depends-on:
assert-h
extensions
+sys_types
limits-h-c++-tests
configure.ac:
diff --git a/tests/test-limits-h.c b/tests/test-limits-h.c
index d7cfba7131..253d2362e7 100644
--- a/tests/test-limits-h.c
+++ b/tests/test-limits-h.c
@@ -94,6 +94,10 @@ unsigned long long limits11[] = { ULLONG_MAX };
static_assert (TYPE_MINIMUM (unsigned long long int) == 0);
static_assert (TYPE_MAXIMUM (unsigned long long int) == ULLONG_MAX);
+/* Specified by POSIX, not by ISO C. */
+
+long long limits12[] = { SSIZE_MAX };
+
/* Macros specified by C23 and by ISO/IEC TS 18661-1:2014. */
verify_width (CHAR_WIDTH, CHAR_MIN, CHAR_MAX);
@@ -115,6 +119,13 @@ static_assert (BOOL_MAX == (((1U << (BOOL_WIDTH - 1)) - 1) * 2) + 1);
static_assert (0 < MB_LEN_MAX);
+/* Get ssize_t, size_t. */
+#include <sys/types.h>
+
+static_assert (TYPE_MAXIMUM (ssize_t) == SSIZE_MAX);
+/* Verify that ssize_t has the same width as size_t. */
+static_assert (TYPE_MAXIMUM (size_t) / 2 == SSIZE_MAX);
+
int
main (void)
{
--
2.34.1
