It allows one to spawn a new concurrent process.Going further mutexes and joins. Pthread_self() returns the ID of the thread. If you want to do so, you must then know how the underlying Pthreads implementation represents the thread id. Now, it is not uncommon to print out the thread id of a given thread, for debugging purpose for instance. Like /pthreadequal()/ to compare two thread IDs BTW. So we see that the function pthreadself() is used by a thread for printing its own thread ID.For this reason, we are presenting two examples demonstrating the use of names in pthreads.Pthread_self_named.c (compressed) (384 downloads)Pthread_named_by_parent.c (compressed) (344 downloads)Example 1: The pthread decides for its nameThe following code, creates a pthread which later, it will give itself a meaningful name.// #define _GNU_SOURCE is needed for the resolution of the following warnings//warning: implicit declaration of function ‘pthread_setname_np’ //warning: implicit declaration of function ‘pthread_getname_np’ // #include is needed for the resolution of EXIT_SUCCESS//The thread name is a meaningful C language string, whose length is restricted to 16 characters, including the terminating null byte.// This is the thread that will be called by pthread_create() and it will be executed by the new thread.// We know that the input data pointer is pointing to a thread_info_t so we are casting it to the right type.Struct thread_info_t *thread_info = (struct thread_info_t *) data Const int setname_rv = pthread_setname_np(thread_info->thread_id, "Tom Hanks") Char thread_name Const int getname_rv = pthread_getname_np(thread_info->thread_id, thread_name, MAX_LENGTH_PTHREAD_NAME) //This function always succeeds, returning the calling thread's ID.//Usually pthread_t is defined as follows://so we print pthread_t as an unsigned long intFprintf(stdout, "I am thread with ID '%lu', my name is '%s' and I gave me my name by myself\n", tid, thread_name ) Const int create_rv = pthread_create(&(thread_info.thread_id), NULL, &self_named_thread, (void *) &thread_info) // The pthread_join() function suspends execution of the calling thread until the target thread terminates, unless the target thread has already terminated.Const int join_rv = pthread_join(thread_info.thread_id, NULL) Example 2: The parent decides for the pthread nameThe next code, creates a pthread and the parent gives the thread a meaningful name.// #include is needed for the resolution of unsigned int sleep(unsigned int seconds) //Added an artificial delay for the sake of the example.//Making sure the parent thread gave the pthread a name.Fprintf(stdout, "I am thread with ID '%lu', my name is '%s' and my parent gave me my name\n", tid, thread_name ) Const int setname_rv = pthread_setname_np(thread_info.thread_id, "Bob Marley") Pthread_named_by_parent.
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It literally makes the program stops in order to wait for the end of the selected thread.Doing multiple operations on one target at the same time is very dangerous, the best example I can give is for databases. It requires a pthread_t, which is the thread descriptor, a pointer to a void function and some other parameters that I will not describe here, the function's arguments for instance.Pthread_join is used to link the current thread process to another thread. And then the stdio.h for printf().Pthread_create function is called to create the thread. Then we include unistd.h which is containing the sleep() function.
Mutex can be used to lock the other threads.In practice, we use mutex to tell if the task is locked or unlocked. In this case we should lock the other threads in order to not overload the hard drive with tasks that can corrupt the file.
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