method

pid

ruby latest stable - Class: IO

pid()

public

Returns the process ID of a child process associated with ios. This will be set by IO.popen.

pipe  = IO .popen ("-")
if pipe 
 $stderr.puts  "In parent, child pid is #{pipe.pid}"
else
 $stderr.puts  "In child, pid is #{$$}"
end

produces:

In child, pid  is 26209
In parent, child pid  is 26209

static VALUE
rb_io_pid(VALUE io)
{
 rb_io_t *fptr;
 GetOpenFile(io, fptr);
 if (!fptr->pid)
 return Qnil;
 return PIDT2NUM(fptr->pid);
}