registerbgidriver

Syntax

#include <graphics.h>
int registerbgidriver(void (*driver)(void));

Description

registerbgidriver enables a user to load a driver file and "register" the driver. Once its memory location has been passed to registerbgidriver, initgraph uses the registered driver. A user-registered driver can be loaded from disk onto the heap, or converted to an .OBJ file (using BGIOBJ.EXE) and linked into the .EXE.

Calling registerbgidriver informs the graphics system that the driver pointed to by driver was included at link time. This routine checks the linked-in code for the specified driver; if the code is valid, it registers the code in internal tables.

By using the name of a linked-in driver in a call to registerbgidriver, you also tell the compiler (and linker) to link in the object file with that public name.

Return Value

registerbgidriver returns a negative graphics error code if the specified driver or font is invalid. Otherwise, registerbgidriver returns the driver number.

If you register a user-supplied driver, you must pass the result of registerbgidriver to initgraph as the driver number to be used.

Windows Notes

registerbgidriver is not available in the winbgim implementation.

See also

graphresult

initgraph

installuserdriver

registerbgifont

Example

/* registerbgidriver example */ 

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>

int main(void)
{
   /* request autodetection */
   int gdriver = DETECT, gmode, errorcode;

   /* register a driver that was added into GRAPHICS.LIB */
   errorcode = registerbgidriver(EGAVGA_driver);

   /* report any registration errors */
   if (errorcode < 0) {
      printf("Graphics error: %s\n", grapherrormsg(errorcode));
      printf("Press any key to halt:");
      getch();

      exit(1);               /* terminate with an error code */
   }

   /* initialize graphics and local variables */
   initgraph(&gdriver, &gmode, "");

   /* read result of initialization */
   errorcode = graphresult();
   if (errorcode != grOk) {  /* an error occurred */
      printf("Graphics error: %s\n", grapherrormsg(errorcode));
      printf("Press any key to halt:");
      getch();
      exit(1);               /* terminate with an error code */
   }


   /* draw a line */
   line(0, 0, getmaxx(), getmaxy());

   /* clean up */
   getch();
   closegraph();
   return 0;
}