whichxms

名稱：DOS SVGACC圖形開發庫函式

原型：extern int far whichxms (unsigned int far *xmskbytesavail, unsigned int far *xmshandlesavail)

輸入：無輸入參數

基本介紹

• 中文名：whichxms
• 闡述：DOS SVGACC圖形開發庫函式
• 輸入：無輸入參數
• 輸出：探測到擴展記憶體

名稱

DOS SVGACC圖形開發庫函式

原型

extern int far whichxms (unsigned int far *xmskbytesavail, unsigned int far *xmshandlesavail)

輸入

無輸入參數

輸出

如果探測到擴展記憶體則返回1，否則返回0

xmskbytesavail - 擴展記憶體的空閒大小(千位元組數)

xmshandlesavail - 擴展記憶體的可用大小(千位元組數)

用法

WHICHXMS檢測是否存在擴展記憶體支持，並且安裝相應的庫函式調用。這個函式必須在所有其它擴展記憶體函式調用之前調用。WHICHXMS同時還返回擴展記憶體的空閒大小和可用大小。可用大小是有限制的，一般為32。這個限制可以在CONFIG.SYS檔案中修改擴展記憶體驅動(常用的是與微軟兼容的HIMEM.SYS)命令行來改變。

例子

/*

* show what xms memory is available

*/

#include <stdlib.h>

#include <conio.h>

#include "svgacc.h"

void main(void)

{

int er, mem, handles;

if ( whichxms(&mem,&handles) ) {

printf("an active xms memory manager was found!\n");

printf("a total of %d kb of xms memory

available...\n",mem);

printf("a total of %d xms memory handles

available...\n",handles);

printf(" \n");

if ((mem < 1) || (handles < 1)) {

printf("sorry...there is either no free xms or\n");

printf("no free handles\n");

printf(" \n");

printf("xms support not available...\n");

exit(1);

}

else {

printf(" \n");

printf("xms support is ready and available!\n");

exit(1);

}

}

else {

printf("sorry...no active xms memory manager

found...\n");

printf("make sure you have an xms memory manager\n");

printf("(such as HIMEM.SYS) loaded\n");

printf(" \n");

printf("xms support not available...\n");

exit(1);

}

exit(0);

}