root/opal/mca/event/libevent2022/libevent/sample/event-test.c

DEFINITIONS

1. fifo_read
2. main

   1 /*
   2  * XXX This sample code was once meant to show how to use the basic Libevent
   3  * interfaces, but it never worked on non-Unix platforms, and some of the
   4  * interfaces have changed since it was first written.  It should probably
   5  * be removed or replaced with something better.
   6  *
   7  * Compile with:
   8  * cc -I/usr/local/include -o event-test event-test.c -L/usr/local/lib -levent
   9  */
  10 
  11 #include <event2/event-config.h>
  12 
  13 #include <sys/types.h>
  14 #include <sys/stat.h>
  15 #ifndef WIN32
  16 #include <sys/queue.h>
  17 #include <unistd.h>
  18 #include <sys/time.h>
  19 #else
  20 #include <winsock2.h>
  21 #include <windows.h>
  22 #endif
  23 #include <fcntl.h>
  24 #include <stdlib.h>
  25 #include <stdio.h>
  26 #include <string.h>
  27 #include <errno.h>
  28 
  29 #include <event.h>
  30 
  31 static void
  32 fifo_read(evutil_socket_t fd, short event, void *arg)
  33 {
  34         char buf[255];
  35         int len;
  36         struct event *ev = arg;
  37 #ifdef WIN32
  38         DWORD dwBytesRead;
  39 #endif
  40 
  41         /* Reschedule this event */
  42         event_add(ev, NULL);
  43 
  44         fprintf(stderr, "fifo_read called with fd: %d, event: %d, arg: %p\n",
  45             (int)fd, event, arg);
  46 #ifdef WIN32
  47         len = ReadFile((HANDLE)fd, buf, sizeof(buf) - 1, &dwBytesRead, NULL);
  48 
  49         /* Check for end of file. */
  50         if (len && dwBytesRead == 0) {
  51                 fprintf(stderr, "End Of File");
  52                 event_del(ev);
  53                 return;
  54         }
  55 
  56         buf[dwBytesRead] = '\0';
  57 #else
  58         len = read(fd, buf, sizeof(buf) - 1);
  59 
  60         if (len == -1) {
  61                 perror("read");
  62                 return;
  63         } else if (len == 0) {
  64                 fprintf(stderr, "Connection closed\n");
  65                 return;
  66         }
  67 
  68         buf[len] = '\0';
  69 #endif
  70         fprintf(stdout, "Read: %s\n", buf);
  71 }
  72 
  73 int
  74 main(int argc, char **argv)
  75 {
  76         struct event evfifo;
  77 #ifdef WIN32
  78         HANDLE socket;
  79         /* Open a file. */
  80         socket = CreateFileA("test.txt",        /* open File */
  81                         GENERIC_READ,           /* open for reading */
  82                         0,                      /* do not share */
  83                         NULL,                   /* no security */
  84                         OPEN_EXISTING,          /* existing file only */
  85                         FILE_ATTRIBUTE_NORMAL,  /* normal file */
  86                         NULL);                  /* no attr. template */
  87 
  88         if (socket == INVALID_HANDLE_VALUE)
  89                 return 1;
  90 
  91 #else
  92         struct stat st;
  93         const char *fifo = "event.fifo";
  94         int socket;
  95 
  96         if (lstat(fifo, &st) == 0) {
  97                 if ((st.st_mode & S_IFMT) == S_IFREG) {
  98                         errno = EEXIST;
  99                         perror("lstat");
 100                         exit(1);
 101                 }
 102         }
 103 
 104         unlink(fifo);
 105         if (mkfifo(fifo, 0600) == -1) {
 106                 perror("mkfifo");
 107                 exit(1);
 108         }
 109 
 110         /* Linux pipes are broken, we need O_RDWR instead of O_RDONLY */
 111 #ifdef __linux
 112         socket = open(fifo, O_RDWR | O_NONBLOCK, 0);
 113 #else
 114         socket = open(fifo, O_RDONLY | O_NONBLOCK, 0);
 115 #endif
 116 
 117         if (socket == -1) {
 118                 perror("open");
 119                 exit(1);
 120         }
 121 
 122         fprintf(stderr, "Write data to %s\n", fifo);
 123 #endif
 124         /* Initalize the event library */
 125         event_init();
 126 
 127         /* Initalize one event */
 128 #ifdef WIN32
 129         event_set(&evfifo, (evutil_socket_t)socket, EV_READ, fifo_read, &evfifo);
 130 #else
 131         event_set(&evfifo, socket, EV_READ, fifo_read, &evfifo);
 132 #endif
 133 
 134         /* Add it to the active events, without a timeout */
 135         event_add(&evfifo, NULL);
 136 
 137         event_dispatch();
 138 #ifdef WIN32
 139         CloseHandle(socket);
 140 #endif
 141         return (0);
 142 }
 143