PathRelativePathToA function (shlwapi.h)

Creates a relative path from one file or folder to another.

Syntax

BOOL PathRelativePathToA(
  [out] LPSTR  pszPath,
  [in]  LPCSTR pszFrom,
  [in]  DWORD  dwAttrFrom,
  [in]  LPCSTR pszTo,
  [in]  DWORD  dwAttrTo
);

Parameters

[out] pszPath

Type: LPTSTR

A pointer to a string that receives the relative path. This buffer must be at least MAX_PATH characters in size.

[in] pszFrom

Type: LPCTSTR

A pointer to a null-terminated string of maximum length MAX_PATH that contains the path that defines the start of the relative path.

[in] dwAttrFrom

Type: DWORD

The file attributes of pszFrom. If this value contains FILE_ATTRIBUTE_DIRECTORY, pszFrom is assumed to be a directory; otherwise, pszFrom is assumed to be a file.

[in] pszTo

Type: LPCTSTR

A pointer to a null-terminated string of maximum length MAX_PATH that contains the path that defines the endpoint of the relative path.

[in] dwAttrTo

Type: DWORD

The file attributes of pszTo. If this value contains FILE_ATTRIBUTE_DIRECTORY, pszTo is assumed to be directory; otherwise, pszTo is assumed to be a file.

Return value

Type: BOOL

Returns TRUE if successful, or FALSE otherwise.

Remarks

This function takes a pair of paths and generates a relative path from one to the other. The paths do not have to be fully qualified, but they must have a common prefix, or the function will fail and return FALSE.

For example, let the starting point, pszFrom, be "c:\FolderA\FolderB\FolderC", and the ending point, pszTo, be "c:\FolderA\FolderD\FolderE". PathRelativePathTo will return the relative path from pszFrom to pszTo as: "....\FolderD\FolderE". You will get the same result if you set pszFrom to "\FolderA\FolderB\FolderC" and pszTo to "\FolderA\FolderD\FolderE". On the other hand, "c:\FolderA\FolderB" and "a:\FolderA\FolderD do not share a common prefix, and the function will fail. Note that "\" is not considered a prefix and is ignored. If you set pszFrom to "\FolderA\FolderB", and pszTo to "\FolderC\FolderD", the function will fail.

Examples

#include <windows.h>
#include <iostream.h>
#include "Shlwapi.h"

void main(void)
{
    char szOut[MAX_PATH] = "";
    char szFrom[ ] = "c:\\a\\b\\path";
    char szTo[ ] = "c:\\a\\x\\y\\file";

    cout  <<  "The relative path is relative from: ";
    cout  <<  szFrom;
    cout  <<  "\n";

    cout  <<  "The relative path is relative to: ";
    cout  <<  szTo;
    cout  <<  "\n";

    PathRelativePathTo(szOut,
                       szFrom,
                       FILE_ATTRIBUTE_DIRECTORY,
                       szTo,
                       FILE_ATTRIBUTE_NORMAL);

    cout  <<  "The relative path is: ";
    cout  <<  szOut;
    cout  <<  "\n";
}

OUTPUT:
==================
The relative path is relative from: c:\a\b\path
The relative path is relative to: c:\a\x\y\file
The relative path is: ..\..\x\y\file

Requirements