Programming

I´m implementing a boss/workers thread system, wich interfaces with TCL clients via socket. The client semms to be ok, but in the server some of the functions raises a segmentation fault. I´ve tried everything i could but i´m just a beginner on threads. Can be a memory allocation problem? or what?
Any help will be wellcomed.
Thanks in advance.
Sebastian.

Please Find Attached the project files.

All anyone can tell you is that you have an error somewhere in your code. It is possible that you accidently sent yourself that signal. If it came from the kernel, then you attempted to use a memory address in an invalid way.

A reasonable guess might be that you dereferenced a pointer with a screwy value in it. This could be an error related to your use of malloc. But almost any facility can be used incorrectly to cause a segmentation violation.

If you have no other way of finding this, put statements like:
fprintf(stderr, "Got to point 1 \n");
at various places in your code. You should then be able to move them around until you have a single statement surrounded by fprintf's...and you see the output from the first, then the program bombs, and the second is never executed. At that point you know which statement is causing the error.

The problem may be due to not using thread safe programming methods. Not all libraries are thread safe. For example, libraries (such as GTK+) are not set to thread safe mode by default and must be initialized as thread safe.

On the other hand - Segmentation faults are usually caused by attempting to write to memory that shouldn't be written to (i.e. a buffer overflow) so make sure you are not accidently freeing memory in one thread while attempting to write to that same memory via another thread.

Thanks a lot.
Indeed was a pointer value.
What we did was to initialize every pointer, and now it seems to be ok.

Do you know if the pthread lib is thread safe?

Now we have to implement mutual exclusion on some .txt files.

Shall we use mutexes?
Can you give us any tip or suggestion on that?

Thanks again.

I send you the updated files.