void normvideo(void );选择正常亮度字符。将文本属性（前景和背景）置为启动程序时它所具有的值，来选择标准字符。 void nosound(void );关闭由调用 sound而发声的扬声器。 函数名: open 功 能: 打开一个文件用于读或写 用 法: int open(char *pathname, int access[, int permiss]); 程序例: #include #include #include #include int main(void) { int handle; char msg[] = "Hello world"; if ((handle = open("TEST.$$$", O_CREAT | O_TEXT)) == -1) { perror("Error:"); return 1; } write(handle, msg, strlen(msg)); close(handle); return 0; } 函数名: outport 功 能: 输出整数到硬件端口中 用 法: void outport(int port, int value); 程序例: #include #include int main(void) { int value = 64; int port = 0; outportb(port, value); printf("Value %d sent to port number %d\n", value, port); return 0; } 函数名: outportb 功 能: 输出字节到硬件端口中 用 法: void outportb(int port, char byte); 程序例: #include #include int main(void) { int value = 64; int port = 0; outportb(port, value); printf("Value %d sent to port number %d\n", value, port); return 0; } 函数名: outtext 功 能: 在视区显示一个字符串 用 法: void far outtext(char far *textstring); 程序例: #include #include #include #include int main(void) { /* request auto detection */ int gdriver = DETECT, gmode, errorcode; int midx, midy; /* 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; /* move the C.P. to the center of the screen */ moveto(midx, midy); /* output text starting at the C.P. */ outtext("This "); outtext("is "); outtext("a "); outtext("test."); /* clean up */ getch(); closegraph(); return 0; } 函数名: outtextxy 功 能: 在指定位置显示一字符串 用 法: void far outtextxy(int x, int y, char *textstring); 程序例: #include #include #include #include int main(void) { /* request auto detection */ int gdriver = DETECT, gmode, errorcode; int midx, midy; /* 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; /* output text at the center of the screen*/ /* Note: the C.P. doesn't get changed.*/ outtextxy(midx, midy, "This is a test."); /* clean up */ getch(); closegraph(); return 0; }

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