neobytes/build-aux/m4/l_atomic.m4
Wladimir J. van der Laan a26bad09b6 Merge #8784: Copyright headers for build scripts
0c4e6ce Add MIT license to build-aux/m4 scripts (Luke Dashjr)
3f8a5d8 Trivial: build-aux/m4/l_atomic: Fix typo (Luke Dashjr)
3b4b6dc Add MIT license to autogen.sh and share/genbuild.sh (Luke Dashjr)
f4dffdd Add MIT license to Makefiles (Luke Dashjr)
2018-01-12 08:02:45 +01:00

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dnl Copyright (c) 2015 Tim Kosse <tim.kosse@filezilla-project.org>
dnl Copying and distribution of this file, with or without modification, are
dnl permitted in any medium without royalty provided the copyright notice
dnl and this notice are preserved. This file is offered as-is, without any
dnl warranty.
# Some versions of gcc/libstdc++ require linking with -latomic if
# using the C++ atomic library.
#
# Sourced from http://bugs.debian.org/797228
m4_define([_CHECK_ATOMIC_testbody], [[
#include <atomic>
#include <cstdint>
int main() {
std::atomic<int64_t> a{};
int64_t v = 5;
int64_t r = a.fetch_add(v);
return static_cast<int>(r);
}
]])
AC_DEFUN([CHECK_ATOMIC], [
AC_LANG_PUSH(C++)
AC_MSG_CHECKING([whether std::atomic can be used without link library])
AC_LINK_IFELSE([AC_LANG_SOURCE([_CHECK_ATOMIC_testbody])],[
AC_MSG_RESULT([yes])
],[
AC_MSG_RESULT([no])
LIBS="$LIBS -latomic"
AC_MSG_CHECKING([whether std::atomic needs -latomic])
AC_LINK_IFELSE([AC_LANG_SOURCE([_CHECK_ATOMIC_testbody])],[
AC_MSG_RESULT([yes])
],[
AC_MSG_RESULT([no])
AC_MSG_FAILURE([cannot figure out how to use std::atomic])
])
])
AC_LANG_POP
])