---
name: "pthread_setname_np"
section: "3"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/pthread_setname_np"
---

# pthread\_setname\_np(3)

set/get the name of a thread

## 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 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

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)](/open/2.md).

## ATTRIBUTES

For an explanation of the terms used in this section, see [**attributes**(7)](/attributes/7.md).

| | | |
| --- | --- | --- |
| **Interface** | **Attribute** | **Value** |
| **pthread\_setname\_np**(), **pthread\_getname\_np**() | 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 under 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)](/prctl/2.md), [**pthread\_create**(3)](/pthread_create/3.md), [**pthreads**(7)](/pthreads/7.md)