pthread_setname_np(3) - Linux manual page (original) (raw)
pthreadsetnamenp(3) Library Functions Manual pthreadsetnamenp(3)
NAME top
pthread_setname_np, pthread_getname_np - set/get the name of a
threadLIBRARY top
POSIX threads library (_libpthread_, _-lpthread_)SYNOPSIS top
**#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(pthread_t** _thread_**, char** _name_**[.**_size_**], size_t** _size_**);**DESCRIPTION top
By default, all the threads created using **pthread_create**() inherit
the program name. The **pthread_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'). 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 retrieved. 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 output buffer will be
null terminated.RETURN VALUE top
On success, these functions return 0; on error, they return a
nonzero error number.ERRORS top
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)](../man2/open.2.html).ATTRIBUTES top
For an explanation of the terms used in this section, see
[attributes(7)](../man7/attributes.7.html).
┌──────────────────────────────────────┬───────────────┬─────────┐
│ **Interface** │ **Attribute** │ **Value** │
├──────────────────────────────────────┼───────────────┼─────────┤
│ **pthread_setname_np**(), │ Thread safety │ MT-Safe │
│ **pthread_getname_np**() │ │ │
└──────────────────────────────────────┴───────────────┴─────────┘STANDARDS top
GNU; hence the suffix "_np" (nonportable) in the names.HISTORY top
glibc 2.12.NOTES top
**pthread_setname_np**() internally writes to the thread-specific _comm_
file under the _/proc_ filesystem: _/proc/self/task/_tid_/comm_.
**pthread_getname_np**() retrieves it from the same location.EXAMPLES top
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**
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);
}SEE ALSO top
[prctl(2)](../man2/prctl.2.html), [pthread_create(3)](../man3/pthread%5Fcreate.3.html), [pthreads(7)](../man7/pthreads.7.html)COLOPHON top
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man-pages@man7.orgLinux man-pages 6.10 2024-07-23 pthreadsetnamenp(3)
Pages that refer to this page:PR_SET_NAME(2const), proc_pid_comm(5)