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-rw-r--r--build-aux/m4/l_atomic.m440
1 files changed, 40 insertions, 0 deletions
diff --git a/build-aux/m4/l_atomic.m4 b/build-aux/m4/l_atomic.m4
new file mode 100644
index 0000000000..906724b640
--- /dev/null
+++ b/build-aux/m4/l_atomic.m4
@@ -0,0 +1,40 @@
+# 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 our how to use std::atomic])
+ ])
+ ])
+
+ AC_LANG_POP
+])