pthread_create does not fail, but also does not execute its functions

[ItecKid]

I have this code. pthread_create does not through an error message, however it does not execute it's argument function. See comments in code for better description

void * moveFiles (void * arg);

int main (int argc, char **argv)
{
pthread_t * tid;
int rc = 0;
/*variables count and the files array are correctly populated from other parts of the program */

                tid = malloc (count);
                for (i = 0; i < count; i++) {
                        /* Function moveFile is never executed */
                        rc = pthread_create (&tid[i], NULL, moveFile, (void *)files[i]);
                        if (rc != 0) {
                                /* This error message is also never executed */
                                fprintf (stderr, "Could not create thread!\n");
                                exit (0);
                        }
                }
                for (i = 0; i < count; i++) {
                        /* This causes segfault when it tries to join non-existant threads */
                        pthread_join (tid[i], NULL);
                }
}

void *moveFile (void * arg)
{
        char *file = (char *)arg;
        int in, out;            /* FDs for input and output file */
        char buffer [INT_MAX];  /* Being a little liberal with memory here, please don't mark off! */
        char backup[512]; 
        strcat(backup, ".backup/");
        strcat (backup, file);
        strcat (backup, ".bak");
        printf ("In thread!!!\n");
        printf ("File name is %s\n", file);
        printf ("Backup file is %s\n", backup);
        if ((in = open(file, O_RDONLY)) < 0) {
                printf("Cannot open inputfile!\n");
                exit(0);
        }
        if ((out = open(backup, O_WRONLY|O_CREAT|O_TRUNC, S_IRUSR|S_IRGRP|S_IROTH)) < 0) {
                printf("Cannot open outfile\n");
                exit(1);
        }
        read (in, buffer, INT_MAX);
        write (out, buffer, INT_MAX);
        close (in);
        close (out);
        return NULL;
}

Thanks for any help can provide.

[nezachem]

Most likely, it is dying at line 32. You have to allocate writable memory for the whole backup filename.

[ItecKid]

It is dying not in that function; I before had a print statement which was at the very top of that function and it did not execute; the function is never called.

I should also mention I have had print statements after the call pthread_create which execute.

But, in the interest of good faith (and because it would need to be addressed) I fixed the memory problem.

[nezachem]

> a print statement did not execute means practically nothing. Load it in gdb, set a breakpoint at the moveFile, and run. This is the only way to know for sure what is going on.
I would do it, but I am away from my linux box.

[nezachem]

> a print statement did not execute means practically nothing. Load it in gdb, set a breakpoint at the moveFile, and run. This is the only way to know for sure what is going on.
I would do it, but I am away from my linux box.

[mitrmkar]

In addition to what nezachem stated, it looks like you are also simply exploding the stack with your buffer declaration

char buffer [INT_MAX];

[ItecKid]

> a print statement did not execute means practically nothing. Load it in gdb, set a breakpoint at the moveFile, and run. This is the only way to know for sure what is going on.
I would do it, but I am away from my linux box.

In this instance it does. And yes, I HAVE run it through gdb. The function moveFile is NEVER executed. The seg fault IS at the pthread_join command.

I do appreciate that you are trying to help, but I have no time to check things I know are not wrong.