基本介紹
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",
"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;
break;
}
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;
}
函式名: hardresume
功 能: 硬體錯誤處理函式
用 法: void hardresume(int rescode);
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",
"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;
break;
}
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;
}
函式名: highvideo
功 能: 選擇高亮度文本字元
用 法: void highvideo(void);
程式例:
#include <conio.h>
int main(void)
{
clrscr();
lowvideo();
cprintf("Low Intensity text\r\n");
highvideo();
gotoxy(1,2);
cprintf("High Intensity Text\r\n");
return 0;
}
函式名: hypot
功 能: 計算直角三角形的斜邊長
用 法: double hypot(double x, double y);
程式例:
#include <stdio.h>
#include <math.h>
int main(void)
{
double result;
double x = 3.0;
double y = 4.0;
result = hypot(x, y);
printf("The hypotenuse is: %lf\n", result);
return 0;
}
