函数名: installuserdriver

功 能: 安装设备驱动程序到BGI设备驱动程序表中

用 法: int far installuserdriver(char far *name, int (*detect)(void));

程序例:

#include <graphics.h>

#include <stdlib.h>

#include <stdio.h>

#include <conio.h>

/* function prototypes */

int huge detectEGA(void);

void checkerrors(void);

int main(void)

{

int gdriver, gmode;

/* install a user written device driver */

gdriver = installuserdriver("EGA", detectEGA);

/* must force use of detection routine */

gdriver = DETECT;

/* check for any installation errors */

checkerrors();

/* initialize graphics and local variables */

initgraph(&gdriver, &gmode, "");

/* check for any initialization errors */

checkerrors();

/* draw a line */

line(0, 0, getmaxx(), getmaxy());

/* clean up */

getch();

closegraph();

return 0;

}

/* detects EGA or VGA cards */

int huge detectEGA(void)

{

int driver, mode, sugmode = 0;

detectgraph(&driver, &mode);

if ((driver == EGA) || (driver == VGA))

/* return suggested video mode number */

return sugmode;

else

/* return an error code */

return grError;

}

/* check for and report any graphics errors */

void checkerrors(void)

{

int errorcode;

/* read result of last graphics operation */

errorcode = graphresult();

if (errorcode != grOk)

{

printf("Graphics error: %s\", grapherrormsg(errorcode));

printf("Press any key to halt:");

getch();

exit(1);

}

}