When something expects a "int *", you're not supposed to declare an "int *". That creates an empty pointer, pointing to nowhere, which will probably cause your program to crash when used!
What they want when they demand an "int *" is pointer to an integer, the address of an integer, so they can modify that integer.
Last edited by Corona688; 12-09-2011 at 01:35 PM..
hi there,
i had some trivial questions about this program here. i am kinda confused with these, hope you can help me to understand here. :)
#include<stdio.h>
#include<sys/wait.h>
#include<sys/types.h>
#include<unistd.h>
int main(void)
{
int... (2 Replies)
Hi,
Ho do I differentiate system call from library call?
for example if I am using chmod , how do I find out if it is a system call or library call?
Thanks
Muru (2 Replies)
Did not use 'wait' yet.
How I understand by now the wait works only for child processes, started background.
Is there any other way to watch completion of any, not related process (at least, a process, owned by the same user?)
I need to start a background process, witch will be waiting... (2 Replies)
Hi
I'm studing the system call. I've written a small program that return the time spent in doing some operations. Now I'd like to write one that return the time spent in user mode of a process.
I'm reading that i should use the tms struct:
clock_t times(struct tms *buf);
struct tms {... (2 Replies)
Hi,
I googled a bit, but could not find the answer to my problem.
But I am sure it is a common issue.
I have this code:
#!/bin/perl -w #-d
use strict;
sub remsh_test()
{
my $host = $_;
printf "\n----\n\n";
printf "remsh to $host with system call\n";
my $result = system... (3 Replies)
hi everyone
i wrote a system call and compiled the kernel succesfully...
my system call is in a file in the kernel folder named my_syscall1.c (kernel/my_syscall1.c)
the header file for this system call i added it in the folder include like this include/my_syscall1/my_syscall1.h
my problem is... (2 Replies)
Trying to figure out a load issue with a webserver. I have traced a php script and noticed the following
connect(4, {sa_family=AF_INET, sin_port=htons(3306), sin_addr=inet_addr("XX.XX.XX.XX")}, 16) = -1 EINPROGRESS (Operation now in progress) <0.000035>
poll(, 1, 2000) = 1 () <0.000120>... (5 Replies)
Hi
I have two scripts script1.sh and script2.sh(say this script is a long running).
I want to call script2.sh inside and script1.sh,but when i call script2.sh i dont want to wait for script2 to complete and want this to run in back ground and go on next commands in script 1.sh and finally at the... (2 Replies)
Discussion started by: lijjumathew
2 Replies
LEARN ABOUT OPENDARWIN
wait.h
wait.h(3HEAD) Headers wait.h(3HEAD)NAME
wait.h, wait - wait status
SYNOPSIS
#include <sys/wait.h>
DESCRIPTION
When a process waits for status from its children using either the wait(3C) or waitpid(3C) function, the status returned can be evaluated
with the following macros, defined in <sys/wait.h>. These macros evaluate to integral expressions. The stat argument to these macros is the
integer value returned from wait() or waitpid().
WCOREDUMP(stat) If the value of WIFSIGNALED (stat) is non-zero, this macro evaluates to a non-zero value if a core image of
the terminated child was created.
WEXITSTATUS(stat) If the value of WIFEXITED(stat) is non-zero, this macro evaluates to the exit code that the child process
passed to _exit() (see exit(2)) or exit(3C), or the value that the child process returned from main.
WIFCONTINUED(stat) Evaluates to a non-zero value if status was returned for a child process that has continued.
WIFEXITED(stat) Evaluates to a non-zero value if status was returned for a child process that terminated normally.
WIFSIGNALED(stat) Evaluates to a non-zero value if status was returned for a child process that terminated due to the receipt
of a signal.
WIFSTOPPED(stat) Evaluates to a non-zero value if status was returned for a child process that is currently stopped.
WSTOPSIG(stat) If the value of WIFSTOPPED(stat) is non-zero, this macro evaluates to the number of the signal that caused
the child process to stop.
WTERMSIG(stat) If the value of WIFSIGNALED(stat) is non-zero, this macro evaluates to the number of the signal that
caused the termination of the child process.
The <sys/wait.h> header defines the symbolic constants listed below for use with waitpid(3C).
WNOHANG Do not hang if no status is available; return immediately.
WUNTRACED Report status of stopped child process.
The symbolic constants listed below are defined as possible values for the options argument to waitid(2).
WEXITED Wait for processes that have exited.
WSTOPPED Status is returned for any child that has stopped upon receipt of a signal.
WCONTINUED Status is returned for any child that was stopped and has been continued.
WNOHANG Return immediately if there are no children to wait for.
WNOWAIT Keep the process whose status is returned in infop in a waitable state.
The type idtype_t is defined as an enumeration type whose possible values include the following:
P_ALL
P_PID
P_PGID
The id_t and pid_t types are defined as described in <sys/types.h>.
The siginfo_t type is defined as described in <signal.h>.
The rusage structure is defined as described in <sys/resource.h>.
Inclusion of the <sys/wait.h> header can also make visible all symbols from <signal.h> and <sys/resource.h>.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
SEE ALSO exit(2), waitid(2), exit(3C), wait(3C), waitpid(3C),attributes(5), standards(5)SunOS 5.10 10 Sep 2004 wait.h(3HEAD)