The <condition_variable> header is not small, so <shared_mutex> should
not include it unless it actually needs std::condition_variable, which
is only the case when we don't have pthread_rwlock_t and the POSIX
Timers option.
The <shared_mutex> header would be even smaller if we had a header for
std::condition_variable (separate from std::condition_variable_any).
That's already planned for a future change.
And <memory_resource> would be even smaller if it was possible to get
std::shared_mutex without std::shared_timed_mutex (which depends on
<chrono>). For that to be effective, the synchronized_pool_resource
would have to create its own simpler version of std::shared_lock without
the timed waiting functions. I have no plans to do that.
libstdc++-v3/ChangeLog:
* include/std/shared_mutex: Only include <condition_variable>
when pthread_rwlock_t and POSIX timers are not available.
(__cpp_lib_shared_mutex, __cpp_lib_shared_timed_mutex): Change
value to be type 'long'.
* include/std/version (__cpp_lib_shared_mutex)
(__cpp_lib_shared_timed_mutex): Likewise.
Tested powerpc64le-linux. Committed to trunk.
commit f5d9bc8ae81abe46640477bc9e655aa093947f5f
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Thu Oct 22 18:42:03 2020
libstdc++: Only include <condition_variable> in <shared_mutex> if needed
The <condition_variable> header is not small, so <shared_mutex> should
not include it unless it actually needs std::condition_variable, which
is only the case when we don't have pthread_rwlock_t and the POSIX
Timers option.
The <shared_mutex> header would be even smaller if we had a header for
std::condition_variable (separate from std::condition_variable_any).
That's already planned for a future change.
And <memory_resource> would be even smaller if it was possible to get
std::shared_mutex without std::shared_timed_mutex (which depends on
<chrono>). For that to be effective, the synchronized_pool_resource
would have to create its own simpler version of std::shared_lock without
the timed waiting functions. I have no plans to do that.
libstdc++-v3/ChangeLog:
* include/std/shared_mutex: Only include <condition_variable>
when pthread_rwlock_t and POSIX timers are not available.
(__cpp_lib_shared_mutex, __cpp_lib_shared_timed_mutex): Change
value to be type 'long'.
* include/std/version (__cpp_lib_shared_mutex)
(__cpp_lib_shared_timed_mutex): Likewise.
diff --git a/libstdc++-v3/include/std/shared_mutex b/libstdc++-v3/include/std/shared_mutex
index 414dce3a1b7..7d683a0e0c4 100644
--- a/libstdc++-v3/include/std/shared_mutex
+++ b/libstdc++-v3/include/std/shared_mutex
@@ -33,9 +33,14 @@
#if __cplusplus >= 201402L
-#include <bits/c++config.h>
-#include <condition_variable>
+#include <chrono>
#include <bits/functexcept.h>
+#include <bits/move.h> // move, __exchange
+#include <bits/std_mutex.h> // defer_lock_t
+
+#if ! (_GLIBCXX_USE_PTHREAD_RWLOCK_T && _GTHREAD_USE_MUTEX_TIMEDLOCK)
+# include <condition_variable>
+#endif
namespace std _GLIBCXX_VISIBILITY(default)
{
@@ -49,11 +54,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#ifdef _GLIBCXX_HAS_GTHREADS
#if __cplusplus >= 201703L
-#define __cpp_lib_shared_mutex 201505
+#define __cpp_lib_shared_mutex 201505L
class shared_mutex;
#endif
-#define __cpp_lib_shared_timed_mutex 201402
+#define __cpp_lib_shared_timed_mutex 201402L
class shared_timed_mutex;
/// @cond undocumented
@@ -399,7 +404,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#endif
/// @endcond
-#if __cplusplus > 201402L
+#if __cplusplus >= 201703L
/// The standard shared mutex type.
class shared_mutex
{
@@ -814,7 +819,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
release() noexcept
{
_M_owns = false;
- return std::exchange(_M_pm, nullptr);
+ return std::__exchange(_M_pm, nullptr);
}
// Getters
diff --git a/libstdc++-v3/include/std/version b/libstdc++-v3/include/std/version
index 9c16f2c4e70..ebb50a04d24 100644
--- a/libstdc++-v3/include/std/version
+++ b/libstdc++-v3/include/std/version
@@ -89,7 +89,7 @@
# define __cpp_lib_quoted_string_io 201304
# define __cpp_lib_robust_nonmodifying_seq_ops 201304
# ifdef _GLIBCXX_HAS_GTHREADS
-# define __cpp_lib_shared_timed_mutex 201402
+# define __cpp_lib_shared_timed_mutex 201402L
# endif
# define __cpp_lib_string_udls 201304
# define __cpp_lib_transparent_operators 201510
@@ -157,7 +157,7 @@
#define __cpp_lib_sample 201603
#ifdef _GLIBCXX_HAS_GTHREADS
# define __cpp_lib_scoped_lock 201703
-# define __cpp_lib_shared_mutex 201505
+# define __cpp_lib_shared_mutex 201505L
#endif
#define __cpp_lib_shared_ptr_weak_type 201606
#define __cpp_lib_string_view 201803L
