Added some sanity checks, and made it use the read subdev by default

if no "-s" command line option is given.

diff --git a/demo/gpct_buffered_counting.c b/demo/gpct_buffered_counting.c
index 144f12100fc9a8543666e9d74351f80e4029e576..4bba317a2a29568eeb398e59346a9c765204c8f3 100644 (file)
--- a/demo/gpct_buffered_counting.c
+++ b/demo/gpct_buffered_counting.c
@@ -35,6 +35,36 @@
 #include <ctype.h>
 #include "examples.h"
 
+int check_subdevice(comedi_t *device, int *subdevice, const char *device_filepath)
+{
+       int read_subdevice = comedi_get_read_subdevice(device);
+       if(read_subdevice < 0)
+       {
+               fprintf(stderr, "Device file \"%s\" cannot do streaming input.\n", device_filepath);
+               return -1;
+       }
+       if(*subdevice < 0) *subdevice = read_subdevice;
+       if(read_subdevice != *subdevice)
+       {
+               fprintf(stderr, "You specified subdevice %i, but the read subdevice of device file \"%s\" is %i.\n",
+                       *subdevice, device_filepath, read_subdevice);
+               return -1;
+       }
+       int subdevice_type = comedi_get_subdevice_type(device, *subdevice);
+       if(subdevice_type < 0)
+       {
+               comedi_perror("comedi_get_subdevice_type()");
+               return -1;
+       }
+       if(subdevice_type != COMEDI_SUBD_COUNTER)
+       {
+               fprintf(stderr, "Subdevice is not a counter (type %i), but of type %i.\n",
+                       COMEDI_SUBD_COUNTER, subdevice_type);
+               return -1;
+       }
+       return 0;
+}
+
 int ni_gpct_configure_buffered_event_counting(comedi_t *device, unsigned subdevice)
 {
        int retval;
@@ -125,7 +155,7 @@ int ni_gpct_send_command(comedi_t *device, unsigned subdevice, unsigned n_counts
        return 0;
 }
 
-int ni_gpct_read_and_dump_counts(comedi_t *device, const char *device_filename, unsigned subdevice)
+int ni_gpct_read_and_dump_counts(comedi_t *device, unsigned subdevice)
 {
        char subdevice_filename[100];
        int retval;
@@ -133,18 +163,6 @@ int ni_gpct_read_and_dump_counts(comedi_t *device, const char *device_filename,
        static const unsigned buffer_size = 1000;
        lsampl_t buffer[buffer_size];
 
-       //TODO: allow subdevice file name to be specified as a command-line option (with sensible default)
-#if 0
-       retval = snprintf(subdevice_filename, sizeof(subdevice_filename), "%s_sub%i", device_filename, subdevice);
-       assert(retval < sizeof(subdevice_filename));
-       fd = open(subdevice_filename, O_RDONLY);
-       if(fd < 0)
-       {
-               fprintf(stderr, "error opening subdevice file \"%s\".\n", subdevice_filename);
-               perror("open");
-               return -errno;
-       }
-#endif
        fd = comedi_fileno(device);
        retval = read(fd, buffer, buffer_size * sizeof(lsampl_t));
        while(retval > 0)
@@ -173,6 +191,7 @@ int main(int argc, char *argv[])
        struct parsed_options options;
 
        init_parsed_options(&options);
+       options.subdevice = -1;
        parse_options(&options, argc, argv);
        device = comedi_open(options.filename);
        if(!device)
@@ -180,14 +199,15 @@ int main(int argc, char *argv[])
                comedi_perror(options.filename);
                exit(-1);
        }
-       /*FIXME: check that device is counter */
+       retval = check_subdevice(device, &options.subdevice, options.filename);
+       if(retval < 0) return retval;
        printf("Running buffered event counting on subdevice %d.\n", options.subdevice);
 
        retval = ni_gpct_configure_buffered_event_counting(device, options.subdevice);
        if(retval < 0) return retval;
        retval = ni_gpct_send_command(device, options.subdevice, options.n_scan);
        if(retval < 0) return retval;
-       retval = ni_gpct_read_and_dump_counts(device, options.filename, options.subdevice);
+       retval = ni_gpct_read_and_dump_counts(device, options.subdevice);
        if(retval < 0) return retval;
        return 0;
 }