finding PID of a program and saving to file

light-angel · 01-29-2014, 03:58 AM

hi i hope im posting in the right place here

im helping on writing a program with linux and lua @ the mine we have got this in the program

Code:

--// Store PID
if _OS == "Linux" then
	local rfilename = "/proc/self/stat"
	local rfile, err = io.open(rfilename, "r")
	if rfile then
		local msg = rfile:read("*a")
		rfile:close()
		local wfile, err = io.open (_CONFIGDIR.."pidfile", "w")
		if wfile then
			wfile:write(msg)
			wfile:close()
		end
	end
end

and it outputs

Code:

6143 (lua) R 1 6143 6143 0 -1 4202560 828 0 16 0 1 0 0 0 20 0 1 0 205111863 6316032 862 18446744073709551615 134512640 134629472 4292373680 4292363708 4151641136 0 0 4096 17578 0 0 0 17 0 0 0 9 0 0

is their anyway i can just get it to save the PID and nothing else

thanks in advance for your help

rtmistler · 01-29-2014, 08:09 AM

See getpid() for this:

Quote:

GETPID(2) Linux Programmer's Manual GETPID(2)

NAME
getpid, getppid - get process identification

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

pid_t getpid(void);
pid_t getppid(void);

DESCRIPTION
getpid() returns the process ID of the calling process. (This is often used by routines that generate unique temporary filenames.)

getppid() returns the process ID of the parent of the calling process.