|
Turbo C 2.0、Borland C++库函数及用例(21) int gdriver = DETECT, gmode, errorcode;
int midx, midy;
int stangle = 0, endangle = 360;
int xradius = 100, yradius = 50; /* initialize graphics, 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;
setcolor(getmaxcolor()); /* draw ellipse */
ellipse(midx, midy, stangle, endangle,
xradius, yradius);
/* clean up */
getch();
closegraph();
return 0;
}
函数名: enable
功 能: 开放硬件中断
用 法: void enable(void);
程序例:/* ** NOTE:
This is an interrupt service routine. You can NOT compile
this program with Test Stack Overflow turned on and get an
executable file which will operate correctly.
*/#include <stdio.h>
#include <dos.h>
#include <conio.h>/* The clock tick interrupt */
#define INTR 0X1Cvoid interrupt ( *oldhandler)(void);int count=0;void interrupt handler(void)
{
/*
disable interrupts during the handling of the interrupt
*/
disable();
/* increase the global counter */ count++;
/* re enable interrupts at the end of the handler*/
enable();
/* call the old routine */
oldhandler();
}int main(void)
{
/* save the old interrupt vector */
oldhandler = getvect(INTR);
/* install the new interrupt handler */
setvect(INTR, handler);/* loop until the counter exceeds 20 */
while (count < 20)
printf("count is %d\n",count);/* reset the old interrupt handler */
setvect(INTR, oldhandler); return 0;
}
函数名: eof
功 能: 检测文件结束
用 法: int eof(int *handle);
程序例:#include <sys\stat.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <io.h>int main(void)
{
|
