_getdcwd, _wgetdcwd

Artikel
07/22/2011

Gets the full path of the working directory on the specified drive.

char *_getdcwd( 
   int drive,
   char *buffer,
   int maxlen 
);
wchar_t *_wgetdcwd( 
   int drive,
   wchar_t *buffer,
   int maxlen 
);

Parameters

drive
A non-negative integer that specifies the drive (0 = default drive, 1 = A, 2 = B, and so on).

If the specified drive is not available, or the kind of drive (for example, removable, fixed, CD-ROM, RAM disk, or network drive) cannot be determined, the invalid-parameter handler, which is described in Parameter Validation, is invoked.
buffer
Storage location for the path, or NULL.

If NULL is specified, this function allocates a buffer of at least maxlen size by using malloc, and the return value of _getdcwd is a pointer to the allocated buffer. The buffer can be freed by calling free and passing it the pointer.
maxlen
A nonzero positive integer that specifies the maximum length of the path, in characters: char for _getdcwd and wchar_t for _wgetdcwd.

If maxlen is not greater than zero, the invalid-parameter handler, which is described in Parameter Validation, is invoked.

Return Value

Pointer to a string that represents the full path of the working directory on the specified drive, or NULL, which indicates an error.

If buffer is specified as NULL and there is insufficient memory to allocate maxlen characters, an error occurs and errno is set to ENOMEM. If the length of the path, which includes the terminating null character, exceeds maxlen, an error occurs and errno is set to ERANGE. For more information about these error codes, see errno, _doserrno, _sys_errlist, and _sys_nerr.

Remarks

The _getdcwd function gets the full path of the working directory on the specified drive and stores it at buffer. If the working directory is set to the root, the string ends with a backslash (\). If the working directory is set to a directory other than the root, the string ends with the name of the directory and not with a backslash.

_wgetdcwd is a wide-character version of _getdcwd, and its buffer parameter and return value are wide-character strings. Otherwise, _wgetdcwd and _getdcwd behave identically.

This function is thread-safe even though it depends on GetFullPathName, which is itself not thread-safe. However, you can violate thread safety if your multithreaded application calls both this function and GetFullPathName. For more information, see GetFullPathName at MSDN Library.

The version of this function that has the _nolock suffix behaves identically to this function except that it is not thread-safe and is not protected from interference by other threads. For more information, see _getdcwd_nolock, _wgetdcwd_nolock.

When _DEBUG and _CRTDBG_MAP_ALLOC are defined, calls to _getdcwd and _wgetdcwd are replaced by calls to _getdcwd_dbg and _wgetdcwd_dbg so that you can debug memory allocations. For more information, see_getdcwd_dbg, _wgetdcwd_dbg.

Generic-Text Routine Mappings

Tchar.h routine	_UNICODE and _MBCS not defined	_MBCS defined	_UNICODE defined
_tgetdcwd	_getdcwd	_getdcwd	_wgetdcwd

Requirements

Routine	Required header
_getdcwd	<direct.h>
_wgetdcwd	<direct.h> or <wchar.h>

For more compatibility information, see Compatibility.

Example

See the example in _getdrive.

.NET Framework Equivalent

System::Environment::CurrentDirectory

Change History

Date	History	Reason
October 2010	Defined an invalid drive specification and the resulting error handling. Specified the requirements for thread safety. Clarified several descriptions.	Information enhancement.

October 2010

Defined an invalid drive specification and the resulting error handling. Specified the requirements for thread safety. Clarified several descriptions.

Information enhancement.

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