from where pclose gets pid

Question

in the documention of pclose function there is a part of code which illustrates how the pclose() function might be implemented

int pclose(FILE *stream)

{
    int stat;
    pid_t pid;


    pid = <pid for process created for stream by popen()>
    (void) fclose(stream);
    while (waitpid(pid, &stat, 0) == -1) {
        if (errno != EINTR){
            stat = -1;
            break;
        }
    }
    return(stat);
}

so i'm interesting , form where he gets "pid for process created for stream by popen()". is there some place where this value is stored?

http://stackoverflow.com/questions/9462442/c-get-pid-of-process-opened-with-popen — kugg, Mar 27 '13 at 09:50
thank's @kugg , it's the one of solution of my problem, which I already implemented, but it would be good to use standard function and get that pid but as I understand from comments and answers, it is not possible. — zapredelom, Mar 27 '13 at 09:56
If it helps you may want to look at this [implementation](http://stackoverflow.com/questions/548063/kill-a-process-started-with-popen) — kugg, Mar 27 '13 at 09:58

score 2 · Accepted Answer · answered Mar 27 '13 at 09:46

2

From some internal state owned by the library that implements popen() and pclose(). Most probably it will be stored as a field in the (internal) FILE structure.

answered Mar 27 '13 at 09:46

unwind

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so as i understand , there is no portable way to get this field ? – zapredelom Mar 27 '13 at 09:50
For that, see kugg's comment (i.e. [this link](http://stackoverflow.com/questions/9462442/c-get-pid-of-process-opened-with-popen)). – unwind Mar 27 '13 at 09:51

from where pclose gets pid

1 Answers1