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Full Discussion: Question about execl, replacing process's contents
Top Forums Programming Question about execl, replacing process's contents Post 302987899 by SirSalt on Saturday 17th of December 2016 04:25:16 PM
Old 12-17-2016
Question Question about execl in C, replacing process's contents
I'm reading Operating Systems in Depth by Thomas W. Doeppner, and I have a question about execl. He says it's called after fork(), and that it replaces the text (code) of the current process and replaces it with the code of the new program. But that doesn't make sense to me.

Does that mean process A forks itself and its copy is process B, but process A's code is gone, and in its place is the code from process B?

OR does that mean process A forks itself and its copy is process B; process B loads a program into its text section, and now process B's text section is gone and in its place is the program it loaded?

Edit: I realize I forgot to mention the language the author uses in his examples is C
Last edited by SirSalt; 12-17-2016 at 07:08 PM..
 

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LEARN ABOUT HPUX

setpgrp

setpgrp(2)							System Calls Manual							setpgrp(2)

NAME

       setpgrp - set process group ID

SYNOPSIS

DESCRIPTION

       If  the	calling process is not already a session leader, sets the process group ID of the calling process to the process ID of the calling
       process.  If creates a new session, then the new session has no controlling terminal.

       The function has no effect when the calling process is a session leader.

   Security Restrictions
       Some or all of the actions associated with this system call may require privileges.  See privileges(5) for more information.

RETURN VALUE

       Upon successful completion, returns the new process group ID.

ERRORS

       If fails, no changes occur and (see errno(2)) is set to one of the following values:

	      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.

	      The calling process does not have sufficient privileges.

SEE ALSO

       exec(2), fork(2), getpid(2), getsid(2), kill(2), setpgrp3(2), setsid(2), privileges(5), <unistd.h>.

STANDARDS CONFORMANCE

																	setpgrp(2)
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