02-01-2004
printing ppid,child pid,pid
question: for the below program
i just printed the value for pid, child pid and parent pid
why does it give me 6 values? i assume ppid is 28086
but can't figure out why there are 5 values printed instead of just two!
can someone comment on that!
#include<stdio.h>
#define DIM 8
int main()
{
int pid, i, ans;
int arr[DIM] = {1,2,3,4,5,6,7,8};
pid = fork();
printf("%d\n",pid);
printf("%d\n",getpid());
printf("%d\n",getppid());
}
======
the output is
$./a.out
0
28873
28872
28873
28872
28086
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LEARN ABOUT NETBSD
setpgid
SETPGID(2) BSD System Calls Manual SETPGID(2)
NAME
setpgid, setpgrp -- set process group
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
int
setpgid(pid_t pid, pid_t pgrp);
int
setpgrp(pid_t pid, pid_t pgrp);
DESCRIPTION
setpgid() sets the process group of the specified process pid to the specified pgrp. If pid is zero, then the call applies to the current
process. If pgrp is zero, then the process id of the process specified by pid is used instead.
If the invoker is not the super-user, then the affected process must have the same effective user-id as the invoker or be a descendant of the
invoking process.
RETURN VALUES
setpgid() returns 0 when the operation was successful. If the request failed, -1 is returned and the global variable errno indicates the
reason.
ERRORS
setpgid() will fail and the process group will not be altered if:
[EACCES] The value of 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 functions.
[EINVAL] The value of the pgrp argument is less than zero.
[EPERM] The effective user ID of the requested process is different from that of the caller and the process is not a descendant of
the calling process.
[ESRCH] The value of the pid argument does not match the process ID of the calling process or of a child process of the calling
process.
SEE ALSO
getpgrp(2)
STANDARDS
The setpgid() function conforms to ISO/IEC 9945-1:1990 (``POSIX.1'').
COMPATIBILITY
setpgrp() is identical to setpgid(), and is retained for calling convention compatibility with historical versions of BSD.
BSD
December 18, 2003 BSD