testing/select.c

   1
   2 #include <stdio.h>
   3 #include <comedilib.h>
   4 #include <fcntl.h>
   5 #include <unistd.h>
   6 #include <sys/ioctl.h>
   7 #include <errno.h>
   8 #include <getopt.h>
   9 #include <ctype.h>
  10 #include <math.h>
  11 #include <sys/time.h>
  12 #include <string.h>
  13 #include "comedi_test.h"
  14
  15
  16 #define BUFSZ 10000
  17
  18 int test_read_select(void)
  19 {
  20         comedi_cmd cmd;
  21         char buf[BUFSZ];
  22         unsigned int chanlist[1];
  23         int go;
  24         int total=0;
  25         int ret;
  26         int chunks=0;
  27         int length=100000;
  28         fd_set rdset;
  29         struct timeval timeout;
  30         unsigned int flags;
  31
  32         flags = comedi_get_subdevice_flags(device,subdevice);
  33         if(!(flags&SDF_CMD) || (comedi_get_read_subdevice(device)!=subdevice)){
  34                 printf("not applicable\n");
  35                 return 0;
  36         }
  37
  38         if(comedi_get_cmd_generic_timed(device, subdevice, &cmd, 1, 1)<0){
  39                 printf("E: comedi_get_cmd_generic_timed failed\n");
  40                 return 0;
  41         }
  42
  43         if(realtime)cmd.flags |= TRIG_RT;
  44
  45         cmd.chanlist = chanlist;
  46         cmd.scan_end_arg = 1;
  47         cmd.stop_arg = length;
  48         cmd.chanlist_len = 1;
  49         chanlist[0] = CR_PACK(0,0,0);
  50
  51         //fcntl(comedi_fileno(device),F_SETFL,O_NONBLOCK);
  52
  53         comedi_command(device,&cmd);
  54
  55         go=1;
  56         while(go){
  57                 FD_ZERO(&rdset);
  58                 FD_SET(comedi_fileno(device),&rdset);
  59                 timeout.tv_sec = 0;
  60                 timeout.tv_usec = 10000;
  61                 ret = select(comedi_fileno(device)+1,&rdset,NULL,NULL,&timeout);
  62                 if(ret<0){
  63                         perror("select");
  64                 }else if(ret==0){
  65                         if(verbose)printf("timeout\n");
  66                 }else{
  67                         ret = read(comedi_fileno(device),buf,BUFSZ);
  68                         if(verbose)printf("read==%d\n",ret);
  69                         if(ret<0){
  70                                 if(errno==EAGAIN){
  71                                         printf("E: got EAGAIN!\n");
  72                                 }else{
  73                                         go = 0;
  74                                         perror("read");
  75                                 }
  76                         }else if(ret==0){
  77                                 go = 0;
  78                         }else{
  79                                 total += ret;
  80                                 chunks++;
  81                         }
  82                 }
  83         }
  84
  85         return 0;
  86 }
  87