功 能: 用戶可修改的圖形存儲區分配函式
用 法: void far *far _graphgetmem(unsigned size);
程式例:
#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
#include <alloc.h>
int main(void)
{
/* request autodetection */
int gdriver = DETECT, gmode, errorcode;
int midx, midy;
/* clear the text screen */
clrscr();
printf("Press any key to initialize graphics mode:");
getch();
clrscr();
/* 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 */
}
midx = getmaxx() / 2;
midy = getmaxy() / 2;
/* display a message */
settextjustify(CENTER_TEXT, CENTER_TEXT);
outtextxy(midx, midy, "Press any key to exit graphics mode:");
/* clean up */
getch();
closegraph();
return 0;
}
/* called by the graphics kernel to allocate memory */
void far * far _graphgetmem(unsigned size)
{
printf("_graphgetmem called to allocate %d bytes.\n", size);
printf("hit any key:");
getch();
printf("\n");
/* allocate memory from far heap */
return farmalloc(size);
}
/* called by the graphics kernel to free memory */
void far _graphfreemem(void far *ptr, unsigned size)
{
printf("_graphfreemem called to free %d bytes.\n", size);
printf("hit any key:");
getch();
printf("\n");
/* free ptr from far heap */
farfree(ptr);
}
