In the obsolete LinuxThreads implementation, each of the threads in a process has a different process ID. Pthread_attr_setstacksize(3), the stack size attribute can be explicitly set in the attr argument used to create a thread, in order to obtain a Limit at the time the program started has any value other than "unlimited", then it determines the default stack size of new threads. Under the NPTL threading implementation, if the RLIMIT_STACK soft resource On Linux/x86-32, the default stack size for a new thread is 2 megabytes. Byĭefault, a new thread is created in a joinable state, unless attr was set to create the thread in a detached state (using Making a thread detached is useful for some types of daemon threads whose exit status the application does not need to care about. When a detached thread terminates, its resources are automatically released back to the system: it is not possible to join with the thread in order to Only when a terminated joinable thread has been joined are the last of its resources released back to the Thread to terminate and fetch its exit status. If a thread is joinable, then another thread can call pthread_join(3) to wait for the Policies are being employed, after a call to pthread_create(), it is indeterminate which thread-the caller or the new thread-will next execute.Ī thread may either be joinable or detached. See pthread_self(3) for further information on the thread ID returned in *thread by pthread_create(). No permission to set the scheduling policy and parameters specified in attr. System-wide limit on the number of threads, /proc/sys/kernel/threads-max, was reached. The RLIMIT_NPROC soft resource limit (set via setrlimit(2)), which limits the number of process for a real user ID, was reached or the kernel's Insufficient resources to create another thread, or a system-imposed limit on the number of threads was encountered. On success, pthread_create() returns 0 on error, it returns an error number, and the contents of *thread are undefined. Linux-specific details The new thread inherits copies of the calling thread's capability sets (see capabilities(7)) and CPU affinity mask (see The initial value of the new thread's CPU-time clock is 0 (see pthread_getcpuclockid(3)). The new thread inherits the calling thread's floating-point environment ( fenv(3)). The new thread does not inherit the creating thread's alternate signal stack ( sigaltstack(2)). The set of pending signals for the new thread is empty The new thread inherits a copy of the creating thread's signal mask ( pthread_sigmask(3)). Used to refer to the thread in subsequent calls to other pthreads functions. If attr is NULL, then the thread is created with defaultīefore returning, a successful call to pthread_create() stores the ID of the new thread in the buffer pointed to by thread this identifier is Thread this structure is initialized using pthread_attr_init(3) and related functions. The attr argument points to a pthread_attr_t structure whose contents are used at thread creation time to determine attributes for the new This causes the termination of all threads This is equivalent to calling pthread_exit(3) with the value supplied in the return statement.Īny of the threads in the process calls exit(3), or the main thread performs a return from main(). It calls pthread_exit(3), specifying an exit status value that is available to another thread in the same process that calls pthread_join(3). The new thread terminates in one of the following ways: The new thread starts execution by invoking start_routine() Īrg is passed as the sole argument of start_routine(). The pthread_create() function starts a new thread in the calling process.