pthread_setname_np(3)	    Library Functions Manual	   pthread_setname_np(3)

NAME
     pthread_setname_np, pthread_getname_np - set/get the name of a thread

LIBRARY
     POSIX threads library (libpthread, -lpthread)

SYNOPSIS
     #define _GNU_SOURCE	     /* See feature_test_macros(7) */
     #include <pthread.h>

     int pthread_setname_np(pthread_t thread, const char *name);
     int pthread_getname_np(size_t size;
			    pthread_t thread, char name[size], size_t size);

DESCRIPTION
     By default, all the threads created using pthread_create() inherit the pro-
     gram  name.   The pthread_setname_np() function can be used to set a unique
     name for a thread, which can be useful for debugging multithreaded applica-
     tions.  The thread name is a meaningful C language string, whose length  is
     restricted	 to  16	 characters, including the terminating null byte ('\0').
     The thread argument specifies the thread whose name is to be changed;  name
     specifies the new name.

     The  pthread_getname_np()	function can be used to retrieve the name of the
     thread.  The thread argument specifies the thread whose name is to	 be  re-
     trieved.  The buffer name is used to return the thread name; size specifies
     the number of bytes available in name.  The buffer specified by name should
     be	 at least 16 characters in length.  The returned thread name in the out-
     put buffer will be null terminated.

RETURN VALUE
     On success, these functions return 0; on error, they return a nonzero error
     number.

ERRORS
     The pthread_setname_np() function can fail with the following error:

     ERANGE
	    The length of the string specified pointed to by  name  exceeds  the
	    allowed limit.

     The pthread_getname_np() function can fail with the following error:

     ERANGE
	    The	 buffer	 specified  by	name  and  size 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 in open(2).

ATTRIBUTES
     For  an  explanation  of the terms used in this section, see attributes(7).
     allbox; lbx lb lb l l l.  Interface Attribute Value T{
     pthread_setname_np(), pthread_getname_np() T}   Thread safety  MT-Safe

STANDARDS
     GNU; hence the suffix "_np" (nonportable) in the names.

HISTORY
     glibc 2.12.

NOTES
     pthread_setname_np() internally writes to the thread-specific comm file un-
     der the /proc filesystem:	/proc/self/task/tid/comm.   pthread_getname_np()
     retrieves it from the same location.

EXAMPLES
     The   program  below  demonstrates	 the  use  of  pthread_setname_np()  and
     pthread_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
	 THREADFOO

   Program 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);
     }

SEE ALSO
     prctl(2), pthread_create(3), pthreads(7)

Linux man-pages 6.18		   2026-02-08		   pthread_setname_np(3)