_fullpath, _wfullpath

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06/05/2017

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Creates an absolute or full path name for the specified relative path name.

Syntax

char *_fullpath(   
   char *absPath,  
   const char *relPath,  
   size_t maxLength   
);  
wchar_t *_wfullpath(   
   wchar_t *absPath,  
   const wchar_t *relPath,  
   size_t maxLength   
);

Parameters

absPath
Pointer to a buffer containing the absolute or full path name, or NULL.

relPath
Relative path name.

maxLength
Maximum length of the absolute path name buffer (absPath). This length is in bytes for _fullpath but in wide characters (wchar_t) for _wfullpath.

Return Value

Each of these functions returns a pointer to a buffer containing the absolute path name (absPath). If there is an error (for example, if the value passed in relPath includes a drive letter that is not valid or cannot be found, or if the length of the created absolute path name (absPath) is greater than maxLength), the function returns NULL.

Remarks

The _fullpath function expands the relative path name in relPath to its fully qualified or absolute path and stores this name in absPath. If absPath is NULL, malloc is used to allocate a buffer of sufficient length to hold the path name. It is the responsibility of the caller to free this buffer. A relative path name specifies a path to another location from the current location (such as the current working directory: "."). An absolute path name is the expansion of a relative path name that states the entire path required to reach the desired location from the root of the file system. Unlike _makepath, _fullpath can be used to obtain the absolute path name for relative paths (relPath) that include "./" or "../" in their names.

For example, to use C run-time routines, the application must include the header files that contain the declarations for the routines. Each header file include statement references the location of the file in a relative manner (from the application's working directory):

#include <stdlib.h>

when the absolute path (actual file system location) of the file might be:

\\machine\shareName\msvcSrc\crt\headerFiles\stdlib.h

_fullpath automatically handles multibyte-character string arguments as appropriate, recognizing multibyte-character sequences according to the multibyte code page currently in use. _wfullpath is a wide-character version of _fullpath; the string arguments to _wfullpath are wide-character strings. _wfullpath and _fullpath behave identically except that _wfullpath does not handle multibyte-character strings.

If _DEBUG and _CRTDBG_MAP_ALLOC are both defined, calls to _fullpath and _wfullpath are replaced by calls to _fullpath_dbg and _wfullpath_dbg to allow for debugging memory allocations. For more information, see _fullpath_dbg, _wfullpath_dbg.

This function invokes the invalid parameter handler, as described in Parameter Validation, if maxlen is less than or equal to 0. If execution is allowed to continue, this function sets errno to EINVAL and returns NULL.

Generic-Text Routine Mappings

Tchar.h routine	_UNICODE and _MBCS not defined	_MBCS defined	_UNICODE defined
`_tfullpath`	`_fullpath`	`_fullpath`	`_wfullpath`

If the absPath buffer is NULL, _fullpath calls malloc to allocate a buffer and ignores the maxLength argument. It is the caller's responsibility to deallocate this buffer (using free) as appropriate. If the relPath argument specifies a disk drive, the current directory of this drive is combined with the path.

Requirements

Function	Required header
`_fullpath`	<stdlib.h>
`_wfullpath`	<stdlib.h> or <wchar.h>

For more compatibility information, see Compatibility in the Introduction.

Example

// crt_fullpath.c  
// This program demonstrates how _fullpath  
// creates a full path from a partial path.  
  
#include <stdio.h>  
#include <conio.h>  
#include <stdlib.h>  
#include <direct.h>  
  
void PrintFullPath( char * partialPath )  
{  
   char full[_MAX_PATH];  
   if( _fullpath( full, partialPath, _MAX_PATH ) != NULL )  
      printf( "Full path is: %s\n", full );  
   else  
      printf( "Invalid path\n" );  
}  
  
int main( void )  
{  
   PrintFullPath( "test" );  
   PrintFullPath( "\\test" );  
   PrintFullPath( "..\\test" );  
}

Full path is: C:\Documents and Settings\user\My Documents\test  
Full path is: C:\test  
Full path is: C:\Documents and Settings\user\test

.NET Framework Equivalent

System::IO::File::Create

共用方式為