Please forgive me if this is off-topic: I've written a simple test program with posix threads and a 'glibc' attempt was detected.
The code: -----main.c------- #include <stdio.h> #include <stdlib.h> #include <pthread.h> #include <sys/socket.h> #include <sys/types.h> #include <errno.h> #include <unistd.h> #include "stack.c" /* * THREAD EXPERIMENT * * There are various threads: * I, II and main * thread I repeatly pushes to 'stck' a value (NTIMES times) * thread II then pop repeatly and show the value (NTIMES-1 times) * main thread then pushes the last values and quit */ #define NTIMES 10000000 #define die(msg) do { perror(msg); exit(1); } while(0) void * doPush(void * data); void * doPop(void * data); struct pack{ Stack stck; pthread_mutex_t mutex; }; int main(int argc, char *argv[]){ void *trashbin; pthread_t peer[2]; struct pack pck; //initialize pck mutex if( pthread_mutex_init(&( pck.mutex), NULL) != 0 ) die("pthread_mutex_init"); //and make it multi-threaded if( pthread_create(&peer[0], NULL, doPush, (void*)&pck) != 0 ) die("pthread_create"); if( pthread_create(&peer[1], NULL, doPop, (void*)&pck) != 0 ) die("pthread_create"); //wait all threads do their stuff pthread_join(peer[0],&trashbin); pthread_join(peer[1],&trashbin); pthread_mutex_lock( &(pck.mutex) ); printf("Last one: %c\n", pop( &(pck.stck) )); pthread_mutex_unlock( &(pck.mutex) ); //destroy pck mutex if( pthread_mutex_destroy( &( pck.mutex) ) != 0 ) die("pthread_mutex_destroy"); return 0; } void * doPush(void * data){ struct pack * pck = (struct pack *)data; int x; for(x=0;x<NTIMES;x++){ int chr; chr = x%('z'-'a'+1); chr += 'a'; //try to push the data... using mutex! pthread_mutex_lock( &(pck->mutex) ); push( &(pck->stck), (void*)chr ); pthread_mutex_unlock( &(pck->mutex) ); } pthread_exit( NULL ); } void * doPop(void * data){ struct pack * pck = (struct pack *)data; int x; for(x=0;x<(NTIMES-1);x++){ pthread_mutex_lock( &(pck->mutex) ); printf("%c ", pop( &(pck->stck) ) ); pthread_mutex_unlock( &(pck->mutex) ); } printf("\n"); pthread_exit( NULL ); } ---------------------- -----stack.c------- #ifndef STACK_C #define STACK_C 1 #include <stdlib.h> struct stack { void * el; struct stack *next; }; typedef struct stack * Stack; void stackInit(Stack * stck){ *stck = NULL; return; } //pushes an element to the stack void push(Stack * stck, void * el){ struct stack * ne; ne = malloc(sizeof(struct stack)); ne->el = el; ne->next = *stck; *stck = ne; return; } //pops an element from stack //return NULL if there's no element in the stack void * pop(Stack * stck){ struct stack * de; void * el; de = *stck; *stck = (*stck)->next; if(de != NULL ){ el = de->el; free(de); } else el = NULL; return el; } #endif ----------------------