Re: [RFC] set the thread name

(cc to linux-api)

Hi,

On Tue, Jun 16, 2009 at 20:39, Stefani Seibold[off-list ref] wrote:

quoted

Currently it is not easy to identify a thread in linux, because there is
no thread name like in some other OS.

If there were are thread name then we could extend a kernel segv message
and the /proc/<pid>/task/<tid>/... entries by a TName value like this:

prctl(PR_SET_NAME, ...) works perfectly here.

Oops, but man page describe another thing.

       PR_SET_NAME
              (Since Linux 2.6.9) Set the process name for the calling process
              to arg2.                    ^^^^^^^^^^^^

Should we change man page? or change implementation?

I bet many developer assume the implementation is right.

Bert

/* -*- c -*- */

#define _GNU_SOURCE
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <stdbool.h>
#include <math.h>
#include <pthread.h>
#include <sys/prctl.h>

void *
thread(void *arg)
{
    unsigned long i = (unsigned long)arg;
    char comm[16];
    snprintf(comm, sizeof comm, "task %02lu", i);
    prctl(PR_SET_NAME, comm, 0l, 0l, 0l);

    sleep(10);

    return NULL;
}

int
main(int ac, char *av[])
{
    pthread_t thr;
    unsigned long i, n = 10;
    char comm[16];

    printf("%u\n", getpid());
    sleep(5);
    snprintf(comm, sizeof comm, "master");
    prctl(PR_SET_NAME, comm, 0l, 0l, 0l);
    sleep(5);

    for (i = 0; i < n; i++)
        pthread_create(&thr, NULL, thread, (void *)i);

    pthread_join(thr, NULL);

    return 0;
}

quoted

Greetings,
Stefani


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