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NAME |LIBRARY |SYNOPSIS |DESCRIPTION |ERRORS |ATTRIBUTES |STANDARDS |HISTORY |EXAMPLES |SEE ALSO |COLOPHON | |
pthread_g...efault_np(3) Library Functions Manualpthread_g...efault_np(3)pthread_getattr_default_np, pthread_setattr_default_np, - get or set default thread-creation attributes
POSIX threads library (libpthread,-lpthread)
#define _GNU_SOURCE/* See feature_test_macros(7) */#include <pthread.h>int pthread_getattr_default_np(pthread_attr_t *attr);int pthread_setattr_default_np(const pthread_attr_t *attr);
Thepthread_setattr_default_np() function sets the default attributes used for creation of a new thread—that is, the attributes that are used whenpthread_create(3) is called with a second argument that is NULL. The default attributes are set using the attributes supplied in*attr, a previously initialized thread attributes object. Note the following details about the supplied attributes object: • The attribute settings in the object must be valid. • Thestack address attribute must not be set in the object. • Setting thestack size attribute to zero means leave the default stack size unchanged. Thepthread_getattr_default_np() function initializes the thread attributes object referred to byattr so that it contains the default attributes used for thread creation.
EINVAL(pthread_setattr_default_np()) One of the attribute settings inattr is invalid, or the stack address attribute is set inattr.ENOMEM(pthread_setattr_default_np()) Insufficient memory.
For an explanation of the terms used in this section, seeattributes(7). ┌──────────────────────────────────────┬───────────────┬─────────┐ │Interface│Attribute│Value│ ├──────────────────────────────────────┼───────────────┼─────────┤ │pthread_getattr_default_np(), │ Thread safety │ MT-Safe │ │pthread_setattr_default_np() │ │ │ └──────────────────────────────────────┴───────────────┴─────────┘
GNU; hence the suffix "_np" (nonportable) in their names.
glibc 2.18.
The program below usespthread_getattr_default_np() to fetch the default thread-creation attributes and then displays various settings from the returned thread attributes object. When running the program, we see the following output: $./a.out; Stack size: 8388608 Guard size: 4096 Scheduling policy: SCHED_OTHER Scheduling priority: 0 Detach state: JOINABLE Inherit scheduler: INHERITProgram source #define _GNU_SOURCE #include <err.h> #include <pthread.h> #include <sched.h> #include <stdio.h> #include <stdlib.h> static void display_pthread_attr(pthread_attr_t *attr) { int s; size_t stacksize; size_t guardsize; int policy; struct sched_param schedparam; int detachstate; int inheritsched; s = pthread_attr_getstacksize(attr, &stacksize); if (s != 0) errc(EXIT_FAILURE, s, "pthread_attr_getstacksize"); printf("Stack size: %zu\n", stacksize); s = pthread_attr_getguardsize(attr, &guardsize); if (s != 0) errc(EXIT_FAILURE, s, "pthread_attr_getguardsize"); printf("Guard size: %zu\n", guardsize); s = pthread_attr_getschedpolicy(attr, &policy); if (s != 0) errc(EXIT_FAILURE, s, "pthread_attr_getschedpolicy"); printf("Scheduling policy: %s\n", (policy == SCHED_FIFO) ? "SCHED_FIFO" : (policy == SCHED_RR) ? "SCHED_RR" : (policy == SCHED_OTHER) ? "SCHED_OTHER" : "[unknown]"); s = pthread_attr_getschedparam(attr, &schedparam); if (s != 0) errc(EXIT_FAILURE, s, "pthread_attr_getschedparam"); printf("Scheduling priority: %d\n", schedparam.sched_priority); s = pthread_attr_getdetachstate(attr, &detachstate); if (s != 0) errc(EXIT_FAILURE, s, "pthread_attr_getdetachstate"); printf("Detach state: %s\n", (detachstate == PTHREAD_CREATE_DETACHED) ? "DETACHED" : (detachstate == PTHREAD_CREATE_JOINABLE) ? "JOINABLE" : "???"); s = pthread_attr_getinheritsched(attr, &inheritsched); if (s != 0) errc(EXIT_FAILURE, s, "pthread_attr_getinheritsched"); printf("Inherit scheduler: %s\n", (inheritsched == PTHREAD_INHERIT_SCHED) ? "INHERIT" : (inheritsched == PTHREAD_EXPLICIT_SCHED) ? "EXPLICIT" : "???"); } int main(void) { int s; pthread_attr_t attr; s = pthread_getattr_default_np(&attr); if (s != 0) errc(EXIT_FAILURE, s, "pthread_getattr_default_np"); display_pthread_attr(&attr); exit(EXIT_SUCCESS); }pthread_attr_getaffinity_np(3),pthread_attr_getdetachstate(3),pthread_attr_getguardsize(3),pthread_attr_getinheritsched(3),pthread_attr_getschedparam(3),pthread_attr_getschedpolicy(3),pthread_attr_getscope(3),pthread_attr_getstack(3),pthread_attr_getstackaddr(3),pthread_attr_getstacksize(3),pthread_attr_init(3),pthread_create(3),pthreads(7)
This page is part of theman-pages (Linux kernel and C library user-space interface documentation) project. Information about the project can be found at ⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report for this manual page, see ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩. This page was obtained from the tarball man-pages-6.15.tar.gz fetched from ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on 2025-08-11. If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up- to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which isnot part of the original manual page), send a mail to man-pages@man7.orgLinux man-pages 6.15 2025-05-17pthread_g...efault_np(3)Pages that refer to this page:pthread_attr_init(3), pthread_create(3)
HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. | |