This example gets information about the installed devices and displays it. Some return code checking was omitted for brevity.

 #define INCL_DOSDEVICES   /* Device values */
 #define INCL_DOSERRORS    /* Error values */
 #include <os2.h>
 #include <stdio.h>

int main(VOID) {

 BYTE    Model      = 0,  /* Model number */
         SubModel   = 0,  /* Submodel */
         Adapter    = 0,  /* Display adapter type */
         CoProc     = 0,  /* Math coprocessor installed? */
         Printers   = 0;  /* Number of printers */

 APIRET  rc         = NO_ERROR; /* Return code */

    rc = DosDevConfig(&Model, DEVINFO_MODEL);
    if (rc != NO_ERROR) {
       printf("DosDevConfig error:  return code = %u\n", rc);
       return 1;
    }

    rc = DosDevConfig(&SubModel, DEVINFO_SUBMODEL);
    printf("    Model/SubModel:  %d / %d\n", Model, SubModel);

    rc = DosDevConfig(&Adapter, DEVINFO_ADAPTER);
    printf("      Display type:  %s\n", (Adapter ? "Color" : "Monochrome"));

    rc = DosDevConfig(&CoProc, DEVINFO_COPROCESSOR);
    printf(" Math co-processor?  %s\n", (CoProc ? "Yes" : "No"));

    rc = DosDevConfig(&Printers, DEVINFO_PRINTER);
    printf("Number of printers:  %d\n", Printers);

    return NO_ERROR;
}