08-23-2001
Threading
I thibk you should do some reading on how write threaded programs.
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1. Programming
I run this code, actually I want to both processes print the message from "data". But only one does. What happens? Anyone can help?
#include <stdio.h>
main(){
int fd, pid;
char x;
fd = open("data",0); /* open file "data" */
pid = fork();
if(pid != 0){
wait(0);
... (2 Replies)
Discussion started by: Herman
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2. Programming
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#define MAX_COUNT 200
#define BUF_SIZE 100
void main(void)
{
pid_t pid;
int i;
char buf;
fork();
pid = getpid();
for (i = 1; i <= MAX_COUNT; i++) {
sprintf(buf,... (2 Replies)
Discussion started by: MKSRaja
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3. Programming
Hello all.
I'm developing a filetransfer application, which is supposed to work sort of like dcc, with multiple transfers etc. Now i wonder what the best way to manage the transfers is. Should i fork() for each new transfer, hogging loads of memory or use pthreads? Maybe I can use select to see... (0 Replies)
Discussion started by: crippe
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4. Programming
hi all
About this code
for (i = 1; i < n; i++)
if ((childpid = fork()) <= 0)
break;
I really can't understand the output .
and the way fork () return the value .
how about the process Id ,the child process Id and the parent ID
in this case
so please answer me soon (5 Replies)
Discussion started by: iwbasts
5 Replies
5. Programming
Hi everybody,
I wanna write a code to understand how fork works.
my target
--------------
-Parent creates a file(called temp) and writes into this file "1".Then it closes the file.
-Then parent creates a child and wait until execution of this child ends.
-Then child opens the same... (3 Replies)
Discussion started by: alexicopax
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6. UNIX for Advanced & Expert Users
Hi,
I wrote a simple program for understanding the fork command. The code is as below
int main(void)
{
fork(); printf("hi 1 \n");
fork(); printf("hi 2 \n");
fork(); printf("hi 3 \n");
}
I am getting a variation in the number of times the printf is called if i remove the \n from each of... (1 Reply)
Discussion started by: xyz123456
1 Replies
7. Programming
Hi,
I wrote a simple program for understanding the fork command. The code is as below
int main(void)
{
fork(); printf("hi 1 \n");
fork(); printf("hi 2 \n");
fork(); printf("hi 3 \n");
}
I am getting a variation in the number of times the printf is called if i remove the \n from each... (2 Replies)
Discussion started by: xyz123456
2 Replies
8. Programming
does fork() spawn only the parent process, what if fork() is looped, does it spawn the parent and the child? (4 Replies)
Discussion started by: Peevish
4 Replies
9. UNIX for Dummies Questions & Answers
I'm trying to run a simple test on how to use fork(), i'm able to execute the child process first then the parent, but how can I execute parent then child..?
Thanks! (1 Reply)
Discussion started by: l flipboi l
1 Replies
10. Programming
I understand that fork create a child but I need very simple example that make child useful....
I mean how will make the program faster anyone explain with code plz
using C plz (2 Replies)
Discussion started by: fwrlfo
2 Replies
LEARN ABOUT HPUX
pthread_rwlock_trywrlock
pthread_rwlock_wrlock(3T) pthread_rwlock_wrlock(3T)
NAME
pthread_rwlock_wrlock(), pthread_rwlock_trywrlock() - lock or attempt to lock a read-write lock for writing
SYNOPSIS
PARAMETERS
rwlock Pointer to the read-write lock to be locked for writing.
DESCRIPTION
The function applies a write lock to the read-write lock object referenced by rwlock. The calling thread acquires the write lock if no
other thread (reader or writer) holds the read-write lock rwlock. Otherwise, the thread blocks (that is, it does not return from the call)
until it can acquire the lock. Results are undefined if the calling thread holds the read-write lock (whether a read or a write lock) at
the time the call is made.
The function applies a write lock as in the function with the exception that the function fails if any thread currently holds rwlock (for
reading or writing).
Results are undefined if any of these functions are called with an uninitialized read-write lock.
If a signal is delivered to a thread waiting for a read-write lock, upon return from the signal handler, the thread shall resume waiting
for the read-write lock as if it was not interrupted.
RETURN VALUE
Upon successful completion, and return zero. Otherwise, an error number is returned to indicate the error (the variable is not set).
ERRORS
If any of the following occur, the function returns the corresponding error number:
[EBUSY] The read-write lock rwlock could not be acquired for writing because it was already locked for reading or writing.
For each of the following conditions, if the condition is detected, the and functions return the corresponding error number:
[EINVAL] The value specified by rwlock does not refer to an initialized read-write lock.
[EDEADLK] The current thread already owns the read-write lock for reading or writing.
AUTHOR
and were developed by X/Open.
SEE ALSO
pthread_rwlock_init(3T), pthread_rwlock_destroy(3T), pthread_rwlock_tryrdlock(3T), pthread_rwlock_rdlock(3T), pthread_rwlock_unlock(3T).
STANDARDS CONFORMANCE
Pthread Library pthread_rwlock_wrlock(3T)