1# pid_t.m4 serial 4
2dnl Copyright (C) 2020-2021 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7# The following implementation works around a problem in autoconf <= 2.69.
8m4_version_prereq([2.70], [], [
9
10dnl Define pid_t if the headers don't define it.
11AC_DEFUN([AC_TYPE_PID_T],
12[
13  AC_CHECK_TYPE([pid_t],
14    [],
15    [dnl On 64-bit native Windows, define it to the equivalent of 'intptr_t'
16     dnl (= 'long long' = '__int64'), because that is the return type
17     dnl of the _spawnv* functions
18     dnl <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/spawnvp-wspawnvp>
19     dnl and the argument type of the _cwait function
20     dnl <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/cwait>.
21     dnl Otherwise (on 32-bit Windows and on old Unix platforms), define it
22     dnl to 'int'.
23     AC_COMPILE_IFELSE(
24       [AC_LANG_PROGRAM([[
25          #if defined _WIN64 && !defined __CYGWIN__
26          LLP64
27          #endif
28          ]])
29       ],
30       [gl_pid_type='int'],
31       [gl_pid_type='__int64'])
32     AC_DEFINE_UNQUOTED([pid_t], [$gl_pid_type],
33       [Define as a signed integer type capable of holding a process identifier.])
34    ],
35    [AC_INCLUDES_DEFAULT])
36])
37
38])# m4_version_prereq 2.70
39