problem to debug in threads

Hello
I use SUSE 9.0, GDB 6.1, GCC 3.3.3, eclipse platform 3.0, CDT 2.0
To show the problem I have an exampe file thread1.c.
It was a "Managed Make C Poject " with name thread1 from eclipse. That is the platform eclipse generate the makefile itself.
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Compile the project with a console:
...>make all
Building file: ../thread1.c
gcc -O0 -g3 -Wall -c -fmessage-length=0 -othread1.o ../thread1.c
Finished building: ../thread1.c

Building target: thread1
gcc -othread1 thread1.o -lpthread -lm
Finished building: thread1
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file thread1.c:
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <pthread.h>
#include <string.h>

void *thread_function(void *arg);

char message[] = "Hello World";

int main() {
int res;
pthread_t a_thread;
void *thread_result;
res = pthread_create(&a_thread, NULL, thread_function, (void *)message);
if (res != 0) {
perror("Thread creation failed");
exit(EXIT_FAILURE);
}
printf("Waiting for thread to finish...\n");
res = pthread_join(a_thread, &thread_result);
if (res != 0) {
perror("Thread join failed");
exit(EXIT_FAILURE);
}
printf("Thread joined, it returned %s\n", (char *)thread_result);
printf("Message is now %s\n", message);
exit(EXIT_SUCCESS);
}

void *thread_function(void *arg) {
printf("thread_function is running. Argument was %s\n", (char *)arg);
sleep(3);
strcpy(message, "Bye!");
pthread_exit("Thank you for the CPU time");
}
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I set a breakpoint at the line res = pthread_create(... and the line sleep(3).
I use the ddd (similar the degugger in the eclipse platform) and following error uccures:
DDD Backtrace:
#1 0x080485b1 in main() at thread1.c:15
#0 0x0804844c in ?? ()
DDD Registers:
eax Couldn't get registers: Kein passender Prozess gefunden
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What is the error, that I can not degug threads ?
Thanks for help.

There error is that debugging symbols can't be found in the target.

You need to pass the -g option to gcc when compiling thread1 to put the debugging symbols into thread1. Without that it will be quite hard to make sense of the backtrace, and program symbols just won't be visible at all, except by address.

Thanks for your reply.
But If you can read in my question the compiler option is -g3.
man-page:
"Level 3 includes extra information, such as all the macro definitions present in
the program. Some debuggers support macro expansion when you use -g3."

Kein passender Prozess gefunden

that doesn't seem to be english (at least to me...)
could you translate it for me pls?
plus: did you try to add debug prints to see where the program crashes exactly?
if you didn't maybe you should. would give u a better idea on where to focus the search.
just don't forget to add a \n after the debug print otherwise the buffer won't be written to the screen immediately and could be discarded if a crash occurs.

Originally posted by Stor_G [B]that doesn't seem to be english (at least to me...) could you translate it for me pls?

Yes it's german. "Kein passender Prozess gefunden" translates
to "Couldn't find appropriate process" (or maybe a required one - but approriate
fits better).

Originally posted by Ralf Becker gcc -othread1 thread1.o -lpthread -lm

There is no -g option used to compile this module (thread1). Therefore this module will not contain debugging information, and cannot easily be debugged.

Edit: There will be symbols in thread1.o but I don't think they'll be kept in the executable unless you pass -g here as well.