First off, consider compiling with all warnings enabled. Example: void *read will trigger lots of problems. read, write are standard names for UNIX syscalls.
means that as soon as the two threads are created (assuming they were since you do not check return codes), ALL threads will exit - when you call pthread_exit() from main() it shuts down everything. So if and why your code runs - I cannot see? check out pthread_join().
There are many other issues with your code. There is a concept in programming: 'not even wrong'. Code can be wrong for lots of reasons. But when code goes off into undefined behavior - which yours is doing - it then does not have actual meaning. No offense. Your write function is doing reads -getchar() is a read.
First step: turn on compiler warnings, example:
Code:
gcc -Wall myfile.c
Fix your code until there are ZERO warnings.
Check and obey your return codes.
After you get that organized, please come back with more questions.
i would like advice on the usbject of c programming (in the middle of reading a book on C). could i benefit more if i apply that knowledge in the unix format if i were able to, or would that take the point out of learning C, basically I want to stay away from strying too far away from unix and use... (1 Reply)
I am developing an application in c with Linux OS, where a radio modem working at baud rate 9600 will be attached to PC on serial port. More than four such units will be communicating at one time, so there may be jamming or data corruption. Each module will be transmitting Data packets less than... (2 Replies)
Hello,
I am trying to learn Networking Programming in C in unix enviorment. I want to know how good it is to become a network programmer. i am crazy about Network programming but i also want to opt for the best carreer options. Anybody experienced Network Programmer, please tell me is my... (5 Replies)
Hello!
Can someone advice me which method I will use if I want to communicate with device via RS232 serial port with this requirements:
1. Serial port is opened in non-canonical mode.
2. All the time I need to check is there something to read.
3. If I have to write something I need to write it... (6 Replies)
Can someone help me on suggesting some ways to access the memory content in RAM directly from C/C++ source code.
Please provide me any book name or any URL so that I can get an exhaustive
knowledge over it.
If possible please give me some tips on interacting with hardwares directly
through... (3 Replies)
Hello!
I am working on an application which reads environmental instruments which have serial ports. The application requires a serial port to be present to talk to the device (i.e. /dev/ttyS0 ). In some instances the environmental devices will be 100's of yards away from the computer, so a... (5 Replies)
Hi,
This is my first post here.
I would like to ask: how to connect the barcode scanner to the serial port?
What are the names in the system (in / dev) and serialport1 serialport0?
Please help with this.
Regards. (2 Replies)
Hello,
I am using the termios library to write data that I get from a Bluetooth device to a modem via serial.
The data arrive from the Bluetooth device correctly every 50ms and I have to bypass them on the serial ttyUSB3 where it is connected to a modem connected to a socket with static IP.
The... (10 Replies)
Hello.
I like Linux and C programming language. Allways wanted to understand kernel and become a Linux system programmer. And I also like Objective-C and iOS. These two programming areas have relations:
1. Linux and iOS are UNIX-like systems, POSIX compliant.
2. It is useful to know C language... (2 Replies)
Discussion started by: Rockatansky
2 Replies
LEARN ABOUT DEBIAN
pthread_join
PTHREAD_JOIN(3) Linux Programmer's Manual PTHREAD_JOIN(3)NAME
pthread_join - join with a terminated thread
SYNOPSIS
#include <pthread.h>
int pthread_join(pthread_t thread, void **retval);
Compile and link with -pthread.
DESCRIPTION
The pthread_join() function waits for the thread specified by thread to terminate. If that thread has already terminated, then
pthread_join() returns immediately. The thread specified by thread must be joinable.
If retval is not NULL, then pthread_join() copies the exit status of the target thread (i.e., the value that the target thread supplied to
pthread_exit(3)) into the location pointed to by *retval. If the target thread was canceled, then PTHREAD_CANCELED is placed in *retval.
If multiple threads simultaneously try to join with the same thread, the results are undefined. If the thread calling pthread_join() is
canceled, then the target thread will remain joinable (i.e., it will not be detached).
RETURN VALUE
On success, pthread_join() returns 0; on error, it returns an error number.
ERRORS
EDEADLK
A deadlock was detected (e.g., two threads tried to join with each other); or thread specifies the calling thread.
EINVAL thread is not a joinable thread.
EINVAL Another thread is already waiting to join with this thread.
ESRCH No thread with the ID thread could be found.
CONFORMING TO
POSIX.1-2001.
NOTES
After a successful call to pthread_join(), the caller is guaranteed that the target thread has terminated.
Joining with a thread that has previously been joined results in undefined behavior.
Failure to join with a thread that is joinable (i.e., one that is not detached), produces a "zombie thread". Avoid doing this, since each
zombie thread consumes some system resources, and when enough zombie threads have accumulated, it will no longer be possible to create new
threads (or processes).
There is no pthreads analog of waitpid(-1, &status, 0), that is, "join with any terminated thread". If you believe you need this function-
ality, you probably need to rethink your application design.
All of the threads in a process are peers: any thread can join with any other thread in the process.
EXAMPLE
See pthread_create(3).
SEE ALSO pthread_cancel(3), pthread_create(3), pthread_detach(3), pthread_exit(3), pthread_tryjoin_np(3), pthreads(7)COLOPHON
This page is part of release 3.44 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2008-11-27 PTHREAD_JOIN(3)