dash/build-aux/m4/l_atomic.m4
fanquake c75a0d4c57
Merge bitcoin/bitcoin#29177: build: Fix check whether -latomic needed
f8ca1357c8205ceff732dcfb0d2bad79b40b611b build: Fix check whether `-latomic` needed (Hennadii Stepanov)

Pull request description:

  Clang >=15 still might need linking against `libatomic`.

  We use `std::atomic<std::chrono::seconds>::compare_exchange_strong` in `net_processing.cpp`.

  Addresses the https://github.com/bitcoin/bitcoin/pull/29165#discussion_r1440293694.

ACKs for top commit:
  maflcko:
    lgtm ACK f8ca1357c8205ceff732dcfb0d2bad79b40b611b
  fanquake:
    ACK f8ca1357c8205ceff732dcfb0d2bad79b40b611b

Tree-SHA512: ba8b6a88fd3471a206d068e8a000a053c99cb46d26bd04624418ddb066b3b9664a569ec8a1569af67c96b3e27f13dccbd5e24f985290ac072b6d74c92524e35d
2024-10-24 13:50:33 -05:00

60 lines
1.6 KiB
Plaintext

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.
# Clang, when building for 32-bit,
# and linking against libstdc++, requires linking with
# -latomic if using the C++ atomic library.
# Can be tested with: clang++ test.cpp -m32
#
# Sourced from http://bugs.debian.org/797228
m4_define([_CHECK_ATOMIC_testbody], [[
#include <atomic>
#include <cstdint>
#include <chrono>
using namespace std::chrono_literals;
int main() {
std::atomic<bool> lock{true};
std::atomic_exchange(&lock, false);
std::atomic<std::chrono::seconds> t{0s};
t.store(2s);
auto t1 = t.load();
t.compare_exchange_strong(t1, 3s);
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
])