1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
# ===========================================================================
# https://www.gnu.org/software/autoconf-archive/ax_c_declare_block.html
# ===========================================================================
#
# SYNOPSIS
#
# AX_C_DECLARE_BLOCK
#
# DESCRIPTION
#
# The macro will compile a test program to see whether the compiler does
# allow new variable declarations in the middle of a C statement block,
# i.e. after some non-declaration line. New compilers will allow that
# which makes the behave a bit more like C++ - the gcc did support it for
# quite a time already.
#
# #define DECLARE_BLOCK_NEEDED says they need to be at the beginning of of
# a statement block. Additionally two defines DECLARE_BLOCK { and
# DECLARE_END } are being set. That makes it possible to do the following
# in your source code (which this macro is really made up for):
#
# #define ___ DECLARE_BLOCK
# #define ____ DECLARE_END
#
# int f() {
# char buffer[1024];
# fgets(buffer, 1024, stdin);
# ___ int i; int ii = strlen(buffer);
# for (i=0; i < ii; i++) {
# fputc(buffer[i], stdout);
# }____;
# }
#
# LICENSE
#
# Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 3 of the License, or (at your
# option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
# Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program. If not, see <https://www.gnu.org/licenses/>.
#
# As a special exception, the respective Autoconf Macro's copyright owner
# gives unlimited permission to copy, distribute and modify the configure
# scripts that are the output of Autoconf when processing the Macro. You
# need not follow the terms of the GNU General Public License when using
# or distributing such scripts, even though portions of the text of the
# Macro appear in them. The GNU General Public License (GPL) does govern
# all other use of the material that constitutes the Autoconf Macro.
#
# This special exception to the GPL applies to versions of the Autoconf
# Macro released by the Autoconf Archive. When you make and distribute a
# modified version of the Autoconf Macro, you may extend this special
# exception to the GPL to apply to your modified version as well.
#serial 11
AC_DEFUN([AX_C_DECLARE_BLOCK],[dnl
AC_CACHE_CHECK(
[if C variables must be declared at the beginning of a block],
ax_cv_c_declare_block,[
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>
int f() {
char buffer[1024];
fgets(buffer, 1024, stdin);
int i; int ii = strlen(buffer);
for (i=0; i < ii; i++) {
fputc(buffer[i], stdout);
}
}]],
[])],
[ax_cv_c_declare_block=no], [ax_cv_c_declare_block=yes])])
if test "$ax_cv_c_declare_block" = yes; then
AC_DEFINE([DECLARE_BLOCK_NEEDED],[1],
[if C variables must be declared at the beginning of a block])
AC_DEFINE([DECLARE_BLOCK],[{],
[set to { if variable declarations need a block start before])
AC_DEFINE([DECLARE_END],[}],
[set to } if variable declarations need a block start before])
fi
])
|
