C語言庫函數_-_O開頭

C語言函數 - O開頭

函數名: open

功  能: 打開一個檔案用于讀或寫

用  法: int open(char *pathname, int access[, int permiss]);

程式例:

#include <string.h>

#include <stdio.h>

#include <fcntl.h>

#include <io.h>

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;

}

函數名: outport

功  能: 輸出整數到硬體端口中

用  法: void outport(int port, int value);

程式例:

#include <stdio.h>

#include <dos.h>

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;

}

函數名: outportb

功  能: 輸出位元組到硬體端口中

用  法: void outportb(int port, char byte);

程式例:

#include <stdio.h>

#include <dos.h>

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;

}

函數名: outtext

功  能: 在視區顯示一個字元串

用  法: void far outtext(char far *textstring);

程式例:

#include <graphics.h>

#include <stdlib.h>

#include <stdio.h>

#include <conio.h>

int main(void)

{

  int gdriver = DETECT, gmode, errorcode;

  int midx, midy;

  initgraph(&gdriver, &gmode, "");

  errorcode = graphresult();

  if (errorcode != grOk)  

  {

     printf("Graphics error: %s\n", grapherrormsg(errorcode));

     printf("Press any key to halt:");

     getch();

     exit(1);

  }

  midx = getmaxx() / 2;

  midy = getmaxy() / 2;

  moveto(midx, midy);

  outtext("This ");

  outtext("is ");

  outtext("a ");

  outtext("test.");

  getch();

  closegraph();

  return 0;

}

函數名: outtextxy

功  能: 在指定位置顯示一字元串

用  法: void far outtextxy(int x, int y, char *textstring);

程式例:

#include <graphics.h>

#include <stdlib.h>

#include <stdio.h>

#include <conio.h>

int main(void)

{

  int gdriver = DETECT, gmode, errorcode;

  int midx, midy;

  initgraph( &gdriver, &gmode, "");

  errorcode = graphresult();

  if (errorcode != grOk)  

  {

     printf("Graphics error: %s\n", grapherrormsg(errorcode));

     printf("Press any key to halt:");

     getch();

     exit(1);

  }

  midx = getmaxx() / 2;

  midy = getmaxy() / 2;

  outtextxy(midx, midy, "This is a test.");

  getch();

  closegraph();

  return 0;

}

轉載于:https://blog.51cto.com/liaosy/1213420