04-26-2008
Sure. The reasoning of it is the entire design architecture
behind a session and process group. If you are not familiar with
these unix concepts programatically W.Richard Stevens
is an invaluable resource.
It sounds like you may be coming from a windows environment.
As Perderabo notes the ability for a process to wait
on another processes session or process group introduces
ineradicable security issues for unix and unix-alikes.
A threaded model is more easily adapted because of
shared address space.
My advice is to use threads if you are uncomfortable with the process paradigm.
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LEARN ABOUT MOJAVE
setsid
SETSID(2) BSD System Calls Manual SETSID(2)
NAME
setsid -- create session and set process group ID
SYNOPSIS
#include <unistd.h>
pid_t
setsid(void);
DESCRIPTION
The setsid function creates a new session. The calling process is the session leader of the new session, is the process group leader of a
new process group and has no controlling terminal. The calling process is the only process in either the session or the process group.
Upon successful completion, the setsid function returns the value of the process group ID of the new process group, which is the same as the
process ID of the calling process.
ERRORS
If an error occurs, setsid returns -1 and the global variable errno is set to indicate the error, as follows:
[EPERM] The calling process is already a process group leader, or the process group ID of a process other than the calling process
matches the process ID of the calling process.
LEGACY SYNOPSIS
#include <sys/types.h>
#include <unistd.h>
The include file <sys/types.h> is necessary.
SEE ALSO
setpgid(3), tcgetpgrp(3), tcsetpgrp(3), compat(5)
STANDARDS
The setsid function is expected to be compliant with the IEEE Std 1003.1-1988 (``POSIX.1'') specification.
BSD
June 4, 1993 BSD