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Tricks of the Windows Gam…ming Gurus (2nd Edition)
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vc98
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crt
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drive.c
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C/C++ Source or Header
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1998-06-17
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191 lines
/***
*drive.c - get and change current drive
*
* Copyright (c) 1989-1997, Microsoft Corporation. All rights reserved.
*
*Purpose:
* This file has the _getdrive() and _chdrive() functions
*
*******************************************************************************/
#ifndef _MAC
#include <cruntime.h>
#include <oscalls.h>
#include <mtdll.h>
#include <internal.h>
#include <msdos.h>
#include <errno.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
/***
*int _getdrive() - get current drive (1=A:, 2=B:, etc.)
*
*Purpose:
* Returns the current disk drive
*
*Entry:
* No parameters.
*
*Exit:
* returns 1 for A:, 2 for B:, 3 for C:, etc.
* returns 0 if current drive cannot be determined.
*
*Exceptions:
*
*******************************************************************************/
int __cdecl _getdrive (
void
)
{
ULONG drivenum;
UCHAR curdirstr[_MAX_PATH];
drivenum = 0;
if (GetCurrentDirectory(sizeof(curdirstr), curdirstr))
if (curdirstr[1] == ':')
drivenum = toupper(curdirstr[0]) - 64;
return drivenum;
}
/***
*int _chdrive(int drive) - set the current drive (1=A:, 2=B:, etc.)
*
*Purpose:
* Allows the user to change the current disk drive
*
*Entry:
* drive - the number of drive which should become the current drive
*
*Exit:
* returns 0 if successful, else -1
*
*Exceptions:
*
*******************************************************************************/
int __cdecl _chdrive (
int drive
)
{
char newdrive[3];
if (drive < 1 || drive > 31) {
errno = EACCES;
_doserrno = ERROR_INVALID_DRIVE;
return -1;
}
_mlock(_ENV_LOCK);
newdrive[0] = (char)('A' + (char)drive - (char)1);
newdrive[1] = ':';
newdrive[2] = '\0';
/*
* Set new drive. If current directory on new drive exists, it
* will become the cwd. Otherwise defaults to root directory.
*/
if ( SetCurrentDirectory((LPSTR)newdrive) ) {
_munlock(_ENV_LOCK);
return 0;
}
else {
_dosmaperr(GetLastError());
_munlock(_ENV_LOCK);
return -1;
}
}
#else /* _MAC */
#include <cruntime.h>
#include <ctype.h>
#include <stdlib.h>
#include <macos\osutils.h>
#include <macos\files.h>
#include <macos\errors.h>
/***
*int _getdrive() - get current drive (-1=BootDisk, -2=Second mounted drive, etc.)
*
*Purpose:
* Returns the current disk drive
*
*Entry:
* No parameters.
*
*Exit:
* returns 1 for BootDisk, 2 for Second mounted drive, etc.
* returns 0 if current drive cannot be determined.
*
*Exceptions:
*
*******************************************************************************/
int __cdecl _getdrive (
void
)
{
OSErr osErr;
WDPBRec wdPB;
char st[256];
wdPB.ioNamePtr = &st[0];
osErr = PBHGetVolSync(&wdPB);
if (osErr)
{
return 0;
}
return wdPB.ioWDVRefNum;
}
/***
*int _chdrive(int drive) - set the current drive (-1=BootDisk, -2=Second drive, etc.)
*
*Purpose:
* Allows the user to change the current disk drive
*
*
*Entry:
* drive - the number of drive which should become the current drive
*
*Exit:
* returns 0 if successful, else -1
*
*Exceptions:
*
*******************************************************************************/
int __cdecl _chdrive (
int drive
)
{
OSErr osErr;
WDPBRec wdPB;
wdPB.ioNamePtr = NULL;
wdPB.ioWDDirID = 0;
wdPB.ioVRefNum = drive;
osErr = PBHSetVolSync(&wdPB);
if (osErr)
{
return -1;
}
return 0;
}
#endif /* _MAC */