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#include <malloc.h>
#include <pthread.h>
#include <stdio.h>
/* The key used to associate a log file pointer with each thread. */
static pthread_key_t thread_log_key;
/* Write MESSAGE to the log file for the current thread. */
void write_to_thread_log (const char* message)
{
FILE* thread_log = (FILE*) pthread_getspecific (thread_log_key);
fprintf (thread_log, %s\n, message);
}
/* Close the log file pointer THREAD_LOG. */
void close_thread_log (void* thread_log)
{
fclose ((FILE*) thread_log);
}
void* thread_function (void* args)
{
char thread_log_filename[20];
FILE* thread_log;
/* Generate the filename for this threads log file. */
sprintf (thread_log_filename, thread%d.log, (int) pthread_self ());
/* Open the log file. */
thread_log = fopen (thread_log_filename, w);
/* Store the file pointer in thread-specific data under thread_log_key. */
pthread_setspecific (thread_log_key, thread_log);
write_to_thread_log (Thread starting.);
/* Do work here... */
return NULL;
}
int main ()
{
int i;
pthread_t threads[5];
/* Create a key to associate thread log file pointers in
thread-specific data. Use close_thread_log to clean up the file
pointers. */
pthread_key_create (&thread_log_key, close_thread_log);
/* Create threads to do the work. */
for (i = 0; i < 5; ++i)
pthread_create (&(threads[i]), NULL, thread_function, NULL);
/* Wait for all threads to finish. */
for (i = 0; i < 5; ++i)
pthread_join (threads[i], NULL);
return 0;
} |
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