There is more than one way to define “memory leak”. In particular, there are two primary definitions of “memory leak” that are in common usage among programmers. The first commonly used definition of “memory leak” is, “Memory was allocated and was not subsequently freed before the program terminated.” However, many programmers (rightly) argue that certain … Read more
If you want to run code on many platforms, go for Posix Threads. They are available almost everywhere and are quite mature. On the other hand if you only use Linux/gcc std::thread is perfectly fine – it has a higher abstraction level, a really good interface and plays nicely with other C++11 classes. The C++11 … Read more
While Helgrind can detect locking order violations, for most programs DRD needs less memory to perform its analysis. Also, DRD has support for detached threads. There are more subtle differences too – compare the respective manuals if you want to know more. See also http://valgrind.org/docs/manual/hg-manual.html and http://valgrind.org/docs/manual/drd-manual.html.
When the main thread returns (i.e., you return from the main function), it terminates the entire process. This includes all other threads. The same thing happens when you call exit. You can avoid this by calling pthread_exit. The purpose of pthread_detach is to make it so you don’t need to join with other threads in … Read more
Condition variables should be used as a place to wait and be notified. They are not the condition itself and they are not events. The condition is contained in the surrounding programming logic. The typical usage pattern of condition variables is // safely examine the condition, prevent other threads from // altering it pthread_mutex_lock (&lock); … Read more
If you are using C++11, here is a right way to do this: Foo& getInst() { static Foo inst(…); return inst; } According to new standard there is no need to care about this problem any more. Object initialization will be made only by one thread, other threads will wait till it complete. Or you … Read more
POSIX threads (pthread) is not an implementation, it is a API specification (a standard, on paper, in english) of several functions whose name starts with pthread_ and which are defined in <pthread.h> header. POSIX is also a set of specifications. NPTL is now inside GNU Libc on Linux and is (or at least tries very … Read more
The best place to find that information is from the POSIX standards pages. A NULL mutex attribute gives you an implementation defined default attribute. If you want to know what you can do with attributes, check out the following reference and follow the pthread_mutexattr_* links in the SEE ALSO section. Usually, the default is a … Read more
A thread’s resources are not immediately released at termination, unless the thread was created with the detach state attribute set to PTHREAD_CREATE_DETACHED, or if pthread_detach is called for its pthread_t. An undetached thread will remain terminated state until its identifier is passed to pthread_join or pthread_detach. To sum it up, you have three options: create … Read more
PTHREAD_MUTEX_ADAPTIVE_NP is something that I invented1 while working in the role of a glibc contributor on making LinuxThreads more reliable and perform better. LinuxThreads was the predecessor to glibc’s NPTL library, originally developed as a stand-alone library by Xavier Leroy, who is also well-known as one of the creators of OCaml. The adaptive mutex survived … Read more