How to get the pid of another process in c?

Question

I am using the getpid and get the pid of current process. Now I am try to get the pid of other process using process name. How to get the other process pid?

#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>

int main(void)
{
    printf("My pid:%d\n", getpid());

    return 0;
}

check this : http://stackoverflow.com/questions/8166415/how-to-get-the-pid-of-a-process-in-linux-in-c — Sam Daniel, Jun 09 '16 at 09:22
Apart from the below answer other method can be writing your own kernel module and interacting with it. <-- (its lot of work but give you the id). You can also run a shell script which parses ps command and get you the pid. You can figure out more ways ..... i guess !! — sourav punoriyar, Jun 09 '16 at 10:56

score 7 · Answer 1 · edited Aug 31 '19 at 15:29

7

You could use popen() with the command program pidof to get the pid of any program.

Like this:

char line[total_length];
FILE * command = popen("pidof ...","r");

fgets(line,total_length,command);

pid_t pid = strtoul(line,NULL,10);
pclose(command);

Edit:

Please see: How to get the PID of a process in Linux in C

edited Aug 31 '19 at 15:29

roschach

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answered Jun 09 '16 at 09:24

Felipe Sulser

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score 6 · Answer 2 · answered Jun 09 '16 at 09:21

1: The most common way, used by daemons. Store the pid number in a file/files. Then other processes can easily find them.

2: Portable way, spawn a child process to executes ps with a pipe. Then you can parse the text output and find your target process.

3: Non-portable way, parse the /proc/ filesystem

Often, 1 is combined with 2 or 3, in order to verify that the pid is correct.

How to get the pid of another process in c?

2 Answers2