added error check for mmap() call

diff --git a/demo/mmap.c b/demo/mmap.c
index 25b9b850083226c12cd8716e7074603a67111248..9cbe7783c047903d4e52a01108f1faed254b557b 100644 (file)
--- a/demo/mmap.c
+++ b/demo/mmap.c
@@ -54,6 +54,10 @@ int main(int argc, char *argv[])
 
        map=mmap(NULL,size,PROT_READ,MAP_SHARED,comedi_fileno(dev),0);
        fprintf(stderr,"map=%p\n",map);
+       if( map == MAP_FAILED ){
+               perror( "mmap" );
+               exit(1);
+       }
 
        for(i=0;i<n_chan;i++){
                chanlist[i]=CR_PACK(channel+i,range,aref);