/******************************************************** * An example source module to accompany... * * "Using POSIX Threads: Programming with Pthreads" *     by Brad nichols, Dick Buttlar, Jackie Farrell *     O'Reilly & Associates, Inc. * ******************************************************** * llist_threads.c -- * * Linked list library with threads support */#include "llist_threads.h"#include <stdio.h>#include <stdlib.h>int llist_init (llist_t *llistp) {  int rtn;  llistp->first = NULL;  if ((rtn = pthread_mutex_init(&(llistp->mutex), NULL)) !=0)    fprintf(stderr, "pthread_mutex_init error %d",rtn), exit(1);  return 0;}int llist_insert_data (int index, void *datap, llist_t *llistp) {  llist_node_t *cur, *prev, *new;  int found = FALSE;  pthread_mutex_lock(&(llistp->mutex));  for (cur=prev=llistp->first; cur != NULL; prev=cur, cur=cur->nextp) {    if (cur->index == index) {      free(cur->datap);      cur->datap = datap;      found=TRUE;      break;    }    else if (cur->index > index){      break;    }  }  if (!found) {    new = (llist_node_t *)malloc(sizeof(llist_node_t));    new->index = index;    new->datap = datap;    new->nextp = cur;    if (cur==llistp->first)      llistp->first = new;    else      prev->nextp = new;  }  pthread_mutex_unlock(&(llistp->mutex));  return 0;}int llist_remove_data(int index, void **datapp, llist_t *llistp) {  llist_node_t *cur, *prev;  /* Initialize to "not found" */  *datapp = NULL;  pthread_mutex_lock(&(llistp->mutex));  for (cur=prev=llistp->first; cur != NULL; prev=cur, cur=cur->nextp) {    if (cur->index == index) {      *datapp = cur->datap;      prev->nextp = cur->nextp;      free(cur);      break;    }    else if (cur->index > index){      break;    }  }  pthread_mutex_unlock(&(llistp->mutex));  return 0;}int llist_find_data(int index, void **datapp, llist_t *llistp) {  llist_node_t *cur, *prev;  /* Initialize to "not found" */  *datapp = NULL;  pthread_mutex_lock(&(llistp->mutex));  /* Look through index for our entry */  for (cur=prev=llistp->first; cur != NULL; prev=cur, cur=cur->nextp) {    if (cur->index == index) {      *datapp = cur->datap;       break;    }    else if (cur->index > index){      break;    }  }  pthread_mutex_unlock(&(llistp->mutex));  return 0;}int llist_change_data(int index, void *datap, llist_t *llistp){  llist_node_t *cur, *prev;  int status = -1; /* assume failure */  pthread_mutex_lock(&(llistp->mutex));  for (cur=prev=llistp->first; cur != NULL; prev=cur, cur=cur->nextp) {    if (cur->index == index) {      cur->datap = datap;      prev->nextp = cur->nextp;      free(cur);      status = 0;      break;    }    else if (cur->index > index){      break;    }  }  pthread_mutex_unlock(&(llistp->mutex));  return status;}int llist_show(llist_t *llistp){  llist_node_t *cur;  pthread_mutex_lock(&(llistp->mutex));  printf (" Linked list contains : \n");  for (cur=llistp->first; cur != NULL; cur=cur->nextp) {    printf ("Index: %d\tData: %s \n", cur->index, (char *)cur->datap);      }  pthread_mutex_unlock(&(llistp->mutex));  return 0;}