C語言庫函數_-_H開頭

c語言函數 - h開頭

函數名: harderr

功  能: 建立一個硬體錯誤處理程式

用  法: void harderr(int (*fptr)());

程式例:

/*this program will trap disk errors and prompt

the user for action. try running it with no

disk in drive a: to invoke its functions.*/

#include <stdio.h>

#include <conio.h>

#include <dos.h>

#define ignore  0

#define retry   1

#define abort   2

int buf[500];

/*define the error messages for trapping disk problems*/

static char *err_msg[] = {

   "write protect",

   "unknown unit",

   "drive not ready",

   "unknown command",

   "data error (crc)",

   "bad request",

   "seek error",

   "unknown media type",

   "sector not found",

   "printer out of paper",

   "write fault",

   "read fault",

   "general failure",

   "reserved",

   "invalid disk change"

};

error_win(char *msg)

{

  int retval;

  cputs(msg);

/*prompt for user to press a key to abort, retry, ignore*/

  while(1)

  {

      retval= getch();

      if (retval == 'a' || retval == 'a')

      {

   retval = abort;

   break;

      }

      if (retval == 'r' || retval == 'r')

   retval = retry;

      if (retval == 'i' || retval == 'i')

          retval = ignore;

          break;

  }

  return(retval);

}

/*pragma warn -par reduces warnings which occur

due to the non use of the parameters errval,

bp and si to the handler.*/

#pragma warn -par

int handler(int errval,int ax,int bp,int si)

  static char msg[80];

  unsigned di;

  int drive;

  int errorno;

  di= _di;

/*if this is not a disk error then it was

another device having trouble*/

  if (ax < 0)

     /* report the error */

     error_win("device error");

     /* and return to the program directly requesting abort */

     hardretn(abort);

/* otherwise it was a disk error */

  drive = ax & 0x00ff;

  errorno = di & 0x00ff;

/* report which error it was */

  sprintf(msg, "error: %s on drive %c\r\na)bort, r)etry, i)gnore: ",

   err_msg[errorno], 'a' + drive);

/*

return to the program via dos interrupt 0x23 with abort, retry,

or ignore as input by the user.

*/

  hardresume(error_win(msg));

  return abort;

#pragma warn +par

int main(void)

install our handler on the hardware problem interrupt

  harderr(handler);

  clrscr();

  printf("make sure there is no disk in drive a:\n");

  printf("press any key ....\n");

  getch();

  printf("trying to access drive a:\n");

  printf("fopen returned %p\n",fopen("a:temp.dat", "w"));

  return 0;

函數名: hardresume

功  能: 硬體錯誤處理函數

用  法: void hardresume(int rescode);

/* this program will trap disk errors and prompt the user for action. */

/* try running it with no disk in drive a: to invoke its functions    */

/* define the error messages for trapping disk problems */

/* prompt for user to press a key to abort, retry, ignore */

          retval = abort;

          retval = retry;

/* pragma warn -par reduces warnings which occur due to the non use */

/* of the parameters errval, bp and si to the handler.              */

/* if this is not a disk error then it was another device having trouble */

     /* and return to the program directly

     requesting abort */

          err_msg[errorno], 'a' + drive);

/* return to the program via dos interrupt 0x23 with abort, retry */

/* or ignore as input by the user.  */

/* install our handler on the hardware problem interrupt */

函數名: highvideo

功  能: 選擇高亮度文本字元

用  法: void highvideo(void);

  lowvideo();

  cprintf("low intensity text\r\n");

  highvideo();

  gotoxy(1,2);

  cprintf("high intensity text\r\n");

函數名: hypot

功  能: 計算直角三角形的斜邊長

用  法: double hypot(double x, double y);

#include <math.h>

  double result;

  double x = 3.0;

  double y = 4.0;

  result = hypot(x, y);

  printf("the hypotenuse is: %lf\n", result);