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. |  |
NAME |LIBRARY |SYNOPSIS |DESCRIPTION |RETURN VALUE |ERRORS |ATTRIBUTES |STANDARDS |HISTORY |NOTES |EXAMPLES |SEE ALSO |COLOPHON | |
pthread_setname_np(3) Library Functions Manualpthread_setname_np(3)pthread_setname_np, pthread_getname_np - set/get the name of a thread
POSIX threads library (libpthread,-lpthread)
#define _GNU_SOURCE/* See feature_test_macros(7) */#include <pthread.h>int pthread_setname_np(pthread_tthread, const char *name);int pthread_getname_np(size_t size;pthread_tthread, charname[size], size_tsize);
By default, all the threads created usingpthread_create() inherit the program name. Thepthread_setname_np() function can be used to set a unique name for a thread, which can be useful for debugging multithreaded applications. The thread name is a meaningful C language string, whose length is restricted to 16 characters, including the terminating null byte ('\0'). Thethread argument specifies the thread whose name is to be changed;name specifies the new name. Thepthread_getname_np() function can be used to retrieve the name of the thread. Thethread argument specifies the thread whose name is to be retrieved. The buffername is used to return the thread name;size specifies the number of bytes available inname. The buffer specified byname should be at least 16 characters in length. The returned thread name in the output buffer will be null terminated.On success, these functions return 0; on error, they return a nonzero error number.
Thepthread_setname_np() function can fail with the following error:ERANGEThe length of the string specified pointed to byname exceeds the allowed limit. Thepthread_getname_np() function can fail with the following error:ERANGEThe buffer specified byname andsize is too small to hold the thread name. If either of these functions fails to open/proc/self/task/tid/comm, then the call may fail with one of the errors described inopen(2).
For an explanation of the terms used in this section, seeattributes(7). ┌──────────────────────────────────────┬───────────────┬─────────┐ │Interface│Attribute│Value│ ├──────────────────────────────────────┼───────────────┼─────────┤ │pthread_setname_np(), │ Thread safety │ MT-Safe │ │pthread_getname_np() │ │ │ └──────────────────────────────────────┴───────────────┴─────────┘
GNU; hence the suffix "_np" (nonportable) in the names.
glibc 2.12.
pthread_setname_np() internally writes to the thread-specificcomm file under the/proc filesystem:/proc/self/task/tid/comm.pthread_getname_np() retrieves it from the same location.
The program below demonstrates the use ofpthread_setname_np() andpthread_getname_np(). The following shell session shows a sample run of the program: $./a.out; Created a thread. Default name is: a.out The thread name after setting it is THREADFOO.^Z# Suspend the program [1]+ Stopped ./a.out $ps H -C a.out -o 'pid tid cmd comm' PID TID CMD COMMAND 5990 5990 ./a.out a.out 5990 5991 ./a.out THREADFOO $cat /proc/5990/task/5990/comm a.out $cat /proc/5990/task/5991/comm THREADFOOProgram source #define _GNU_SOURCE #include <err.h> #include <errno.h> #include <pthread.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #define NAMELEN 16 static void * threadfunc(void *parm) { sleep(5); // allow main program to set the thread name return NULL; } int main(int argc, char *argv[]) { pthread_t thread; int rc; char thread_name[NAMELEN]; rc = pthread_create(&thread, NULL, threadfunc, NULL); if (rc != 0) errc(EXIT_FAILURE, rc, "pthread_create"); rc = pthread_getname_np(thread, thread_name, NAMELEN); if (rc != 0) errc(EXIT_FAILURE, rc, "pthread_getname_np"); printf("Created a thread. Default name is: %s\n", thread_name); rc = pthread_setname_np(thread, (argc > 1) ? argv[1] : "THREADFOO"); if (rc != 0) errc(EXIT_FAILURE, rc, "pthread_setname_np"); sleep(2); rc = pthread_getname_np(thread, thread_name, NAMELEN); if (rc != 0) errc(EXIT_FAILURE, rc, "pthread_getname_np"); printf("The thread name after setting it is %s.\n", thread_name); rc = pthread_join(thread, NULL); if (rc != 0) errc(EXIT_FAILURE, rc, "pthread_join"); printf("Done\n"); exit(EXIT_SUCCESS); }prctl(2),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 2025-06-28pthread_setname_np(3)Pages that refer to this page:PR_SET_NAME(2const), proc_pid_comm(5)
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. | |