05-10-2013
Working of exec family of functions
Hi,
I am studying exec family of functions.Its man page says,it replaces the current process image with a new process image. If it replaces the binary,then after returning back,how does it get the previous parameters of the process which called exec?As replacing process image means replacing all its memory sections.
Thanks
Radha
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LEARN ABOUT SUNOS
setpgid
setpgid(2) System Calls setpgid(2)
NAME
setpgid - set process group ID
SYNOPSIS
#include <sys/types.h>
#include <unistd.h>
int setpgid(pid_t pid, pid_t pgid);
DESCRIPTION
The setpgid() function sets the process group ID of the process with ID pid to pgid.
If pgid is equal to pid, the process becomes a process group leader. See intro(2) for more information on session leaders and process group
leaders.
If pgid is not equal to pid, the process becomes a member of an existing process group.
If pid is equal to 0, the process ID of the calling process is used. If pgid is equal to 0, the process specified by pid becomes a process
group leader.
RETURN VALUES
Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error.
ERRORS
The setpgid() function will fail if:
EACCES The pid argument matches the process ID of a child process of the calling process and the child process has successfully
executed one of the exec family of functions (see exec(2)).
EINVAL The pgid argument is less than (pid_t) 0 or greater than or equal to PID_MAX, or the calling process has a controlling ter-
minal that does not support job control.
EPERM The process indicated by the pid argument is a session leader.
EPERM The pid argument matches the process ID of a child process of the calling process and the child process is not in the same
session as the calling process.
EPERM The pgid argument does not match the process ID of the process indicated by the pid argument, and there is no process with
a process group ID that matches pgid in the same session as the calling process.
ESRCH The pid argument does not match the process ID of the calling process or of a child process of the calling process.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
|MT-Level |Async-Signal-Safe |
+-----------------------------+-----------------------------+
SEE ALSO
intro(2), exec(2), exit(2), fork(2), getpid(2), getsid(2), attributes(5), standards(5)
SunOS 5.10 28 Dec 1996 setpgid(2)