path: root/src/corelib/thread/qmutex_linux.cpp
diff options
authorThiago Macieira <>2012-08-02 16:15:22 +0200
committerQt by Nokia <>2012-08-25 10:35:26 +0200
commitc28204066c2d3bae989132ab15e8df437ae38f3d (patch)
tree989935de1629ae724d8826f16244e85907ad7043 /src/corelib/thread/qmutex_linux.cpp
parent98437f0e2edde7f5e49e1a6bea27ef130b58bee4 (diff)
Mark mutex locking and unlocking functions with noexcept
Unlocking a mutex can never throw an exception. That doesn't make sense and our code should make sure it can't happen. Right now, provided that the system-level functions don't throw, we don't either. Locking a mutex cannot throw on Linux because we use futexes directly. A non-recursive mutex is just a futex, whereas a recursive mutex uses a mutex (a futex) to manage a lock count. However, on other platforms, due to the freelist, there can be memory allocation, which means it might throw std::bad_alloc. Not because of the freelist itself (that uses malloc and will just crash if malloc fails) but because of Q_GLOBAL_STATIC. In 5.1, the global static will be noexcept provided the type's constructor is so too (it is, in this case). Change-Id: I4c562383f48de1be7827b9afb512d73eaf0792d5 Reviewed-by: Marc Mutz <> Reviewed-by: Thiago Macieira <>
Diffstat (limited to 'src/corelib/thread/qmutex_linux.cpp')
1 files changed, 3 insertions, 3 deletions
diff --git a/src/corelib/thread/qmutex_linux.cpp b/src/corelib/thread/qmutex_linux.cpp
index a10bd35eff..3ccaeff4e3 100644
--- a/src/corelib/thread/qmutex_linux.cpp
+++ b/src/corelib/thread/qmutex_linux.cpp
@@ -87,7 +87,7 @@ static inline int futexFlags()
return value;
-static inline int _q_futex(void *addr, int op, int val, const struct timespec *timeout)
+static inline int _q_futex(void *addr, int op, int val, const struct timespec *timeout) Q_DECL_NOTHROW
volatile int *int_addr = reinterpret_cast<volatile int *>(addr);
@@ -106,7 +106,7 @@ static inline QMutexData *dummyFutexValue()
return reinterpret_cast<QMutexData *>(quintptr(3));
-bool QBasicMutex::lockInternal(int timeout)
+bool QBasicMutex::lockInternal(int timeout) Q_DECL_NOTHROW
QElapsedTimer elapsedTimer;
if (timeout >= 1)
@@ -147,7 +147,7 @@ bool QBasicMutex::lockInternal(int timeout)
return true;
-void QBasicMutex::unlockInternal()
+void QBasicMutex::unlockInternal() Q_DECL_NOTHROW
QMutexData *d = d_ptr.load();
Q_ASSERT(d); //we must be locked