none/tests/pth_cancel2.c

   1 /********************************************************
   2  * An example source module to accompany...
   3  *
   4  * "Using POSIX Threads: Programming with Pthreads"
   5  *     by Brad nichols, Dick Buttlar, Jackie Farrell
   6  *     O'Reilly & Associates, Inc.
   7  *
   8  ********************************************************
   9  * async_safe --
  10  *
  11  * Example showing macro wrappers for calling non-async
  12  * safe routines when the caller has asynchronous
  13  * cancellation turned on
  14  */
  15
  16 #include <stdlib.h>
  17 #include <stdio.h>
  18 #include <unistd.h>
  19 #include <fcntl.h>
  20 #include <sys/types.h>
  21 #include <sys/stat.h>
  22
  23 #include <pthread.h>
  24
  25
  26 #define async_cancel_safe_read(fd,buf,amt) \
  27    { \
  28       int oldtype; \
  29       pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype); \
  30       if (read(fd,buf,amt) < 0) \
  31          perror("read"),exit(1); \
  32       pthread_setcanceltype(oldtype,NULL); \
  33       pthread_testcancel(); \
  34    }
  35
  36
  37 #define async_cancel_safe_write(fd,buf,amt) \
  38    { \
  39       int oldtype; \
  40       pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype); \
  41       if (write(fd,buf,amt) < 0) \
  42          perror("write"), exit(1); \
  43       pthread_setcanceltype(oldtype,NULL); \
  44       pthread_testcancel(); \
  45    }
  46
  47
  48 static int fd;
  49
  50 void *io(void *arg)
  51 {
  52    int *fd2=(int *)arg;
  53    char buf[20]="String";
  54    int amt=20;
  55
  56    for (;;) {
  57       async_cancel_safe_write(*fd2,buf,amt);
  58       async_cancel_safe_read(*fd2,buf,amt);
  59    }
  60    return(NULL);
  61 }
  62
  63 void *killer(void *arg)
  64 {
  65    pthread_t * target = (pthread_t *)arg;
  66    sleep(1);
  67    pthread_cancel(*target);
  68    return(NULL);
  69 }
  70
  71 extern int
  72 main(void)
  73 {
  74    pthread_t io_thread, killer_thread;
  75
  76    //   extern void *io(void *);
  77    // extern void *killer(void  *);
  78
  79    if ((fd = open(".ktemp",O_CREAT | O_RDWR, 0666)) < 0)
  80       perror("open"), exit(1);
  81
  82    pthread_create(&io_thread,
  83                   NULL,
  84                   io,
  85                   (void *)&fd);
  86    pthread_create(&killer_thread,
  87                   NULL,
  88                   killer,
  89                   (void *)&io_thread);
  90
  91    pthread_join(io_thread, NULL);
  92
  93    pthread_join(killer_thread,NULL);
  94
  95    if ((close(fd)) < 0)
  96      perror("close"),exit(1);
  97    if ((unlink(".ktemp")) < 0)
  98      perror("unlink"),exit(1);
  99
 100    return 0;
 101 }