函数名: _graphfreemem

功 能: 用户可修改的图形存储区释放函数

用 法: void far _graphfreemem(void far *ptr, unsigned size);

程序例:

#include <graphics.h>

#include <stdlib.h>

#include <stdio.h>

#include <conio.h>

#include <alloc.h>

int main(void)

{

/* request auto detection */

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\", 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.\", size);

printf("hit any key:");

getch();

printf("\");

/* 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.\", size);

printf("hit any key:");

getch();

printf("\");

/* free ptr from far heap */

farfree(ptr);

}