Killing a pid in C++

pilot1 · 09-20-2003, 09:17 AM

How is it possible to read a pid from a file (/var/run/httpd.pid in this case) and then kill it, in C++?
I found a thread telling how to kill a process in C, but I didn't know if it was the same for C++ and I didn't have a way to read /var/run/httpd.pid anyways.
Hopefully this isn't a stupid question, I'm very new to C++

Thanks!

kev82 · 09-20-2003, 09:43 AM

something like

Code:

#include <istream>
#include <sys/types.h>
#include <signal.h>

int main()
{
    pid_t pid=0;
    std::ifstream ifs("/var/run/httpd.pid", ios::in);

    ifs >> pid;
    if(pid)
        kill(pid, SIGTERM);
    
    return 0;
}

not tested though, so there might be an error with it.

pilot1 · 09-20-2003, 09:52 AM

Code:

test.cpp:8: variable `std::ifstream ifs' has initializer but incomplete type

That's an error I've never seen, and I can't see anything obviously wrong with the code.
Do you know what might be wrong?

kev82 · 09-20-2003, 09:59 AM

it could be related to the fact i meant #include <fstream> instead of #include <istream> and i meant std::ios::in, try this

Code:

#include <fstream>
#include <sys/types.h>
#include <signal.h>

int main()
{
    pid_t pid=0;
    std::ifstream ifs("/var/run/httpd.pid", std::ios::in);

    ifs >> pid;
    if(pid)
        kill(pid, SIGTERM);
    
    return 0;
}

pilot1 · 09-20-2003, 10:07 AM

It works, thanks!