start by setting up the signal handler before you create the child
And... consider not using functions like printf in a signal handler. See async-signal safe
functions:
Hi everybody,
I'm trying to understand how a parent and child processes interact.
This function( below) basically measures the fork time from the perspective of the parent only.
what i would like to know is how to measure the time from the perspective of parent and child (ie: inserting... (0 Replies)
I want to catch SIGCHLD signal in parent process. I can't use wait() system call to catch SIGCHLD according to project requirment.
Operating system linux 3.1
can any one have a solution for this.
Thanking you,
ranjan (2 Replies)
i am creating children processes using fork system call
every child i create goes to sleep for random time.
when child stops running how can i catch his signal and turminate the child (2 Replies)
Hi All,
I have two ksh script. 1st script calls the 2nd script and the second script calls an 'C' program.
I want 1st script to wait until the 'C' program completes.
I cant able to get the process id for the 'C' program (child process) to make the 1st script to wait for the second... (7 Replies)
Hey all, I need to launch a script from within 2 other scripts that can run independently of the two parent scripts... Im having a hard time doing this, if anyone knows how please let me know.
More detail.
ScriptA (bash), ScriptB (ksh), ScriptC (bash)
ScriptA, launches ScriptB
ScirptB,... (7 Replies)
I'm trying to do a program that makes activate an signal (SINGALARM) when the next child of a son appears but this not works.
I have to caught the next child o the other (pid), to send a singnal which inform a menssage.
It's anything worng in the code?
thanks.
the code:
#include... (2 Replies)
Hello. I want to make a child do some stuff,wait,then the parent does some stuff and then child does some stuff and waits again.I have made the following but it does not work.Can anybody help me?
pid1 = fork();
if (pid1 == -1)
{
perror("Can't create child\n");
... (18 Replies)
Hi, i want that the parent process start before the child, this code doesn't work,
if the child start before the parent it wait for signal, then the father send the signal SIGALRM and the child catch it and call printf;
else the father call printf and send the signal to the child that call its... (1 Reply)
Hello, everyone.
Here's a program:
pid_t pid = fork();
if (0 == pid) // child process
{
execvp ...;
}
I send a signal (such as SIGINT) to the parent process, the child process receive the signal as well as the parent process.
However I don't want to child process to receive the... (7 Replies)
Hi everyone
i am very new to linux , working on bash shell.
I am trying to solve the given problem
1. Create a process and then create children using fork
2. Check the Status of the application for successful running.
3. Kill all the process(threads) except parent and first child... (2 Replies)
Discussion started by: vizz_k
2 Replies
LEARN ABOUT HPUX
vfork
vfork(2) System Calls Manual vfork(2)NAME
vfork - spawn new process; share virtual memory
SYNOPSIS REMARKS
is a higher performance version of that is provided on some systems where a performance advantage can be attained.
If the calling process is multi-threaded, the newly created child process will only contain one thread. This one thread will be a copy of
the thread calling
differs from only in that the child process can share code and data with the calling process (parent process). This speeds cloning activ-
ity significantly at a risk to the integrity of the parent process if is misused.
The use of for any purpose except as a prelude to an immediate or is not supported. Any program that relies upon the differences between
and is not portable across HP-UX systems.
All HP-UX implementations must provide the entry but it is permissible for them to treat it identically to On some implementations the two
are not distinguished because the implementation is as efficient as possible. Other versions may do the same to avoid the overhead of sup-
porting two similar calls.
DESCRIPTION
can be used to create new processes without fully copying the address space of the old process. If a forked process is simply going to do
an (see exec(2)), the data space copied from the parent to the child by is not used. This is particularly inefficient in a paged environ-
ment, making particularly useful. Depending upon the size of the parent's data space, can give a significant performance improvement over
differs from in that the child borrows the parent's memory and thread of control until a call to or an exit (either by a call to or abnor-
mally (see exec(2) and exit(2)). The parent process is suspended while the child is using its resources.
returns 0 in the child's context and (later) the pid of the child in the parent's context.
can normally be used just like It does not work, however, to return while running in the child's context from the procedure which called
since the eventual return from would then return to a no longer existent stack frame.
The window begins at the call and ends when the child completes its call.
RETURN VALUE
Upon successful completion, returns a value of 0 to the child process and returns the process ID of the child process to the parent
process. Otherwise, a value of -1 is returned to the parent, no child process is created, and is set to indicate the error.
ERRORS
fails and no child process is created if any of the following conditions are encountered:
The system-wide limit on the total number of processes under execution
would be exceeded.
The system-imposed limit on the total number of processes under execution
by a single user would be exceeded.
DEPENDENCIES
Servers
Process times for the parent and child processes within the window may be inaccurate.
Parent and child processes share the same stack space within the window. If the size of the stack has been changed within this win-
dow by the child process (return from or call to a function, for example), it is likely that the parent and child processes will be
killed with signal or
In the window, a call to (see signal(2) that installs a catching function can affect handling of the signal by the parent. The par-
ent is not affected if the handling is being set to or or if is used (see sigaction(2)).
AUTHOR
was developed by the University of California, Berkeley.
SEE ALSO exec(2), exit(2), fork(2), sigaction(2), wait(2).
vfork(2)