PRB: FindExecutable() Truncates Result at First Space in LFN (140724)
The information in this article applies to:
- Microsoft Platform Software Development Kit (SDK) 1.0
This article was previously published under Q140724 SYMPTOMS
The FindExecutable function is supposed to retrieve the fully qualified
path to the executable (.exe) file associated with the specified file name.
For example, the following call to FindExecutable() should return the path
to Winword.exe:
FindExecutable ("C:\\README.DOC", NULL, szBuffer);
Assuming Winword.exe is currently in the C:\Msoffice\Winword directory, the
function, upon return, should fill szBuffer with the string
C:\Msoffice\Winword\Winword.Exe.
However, when you use FindExecutable() on a file whose associated
application is in a directory that has a long file name (LFN) that includes
a space, the function truncates the string up at the first space. Going
back to the previous code example, if Winword.exe is located in the
C:\Program Files\My Accessories directory, the function incorrectly returns
the truncated string C:\Program instead of the following expected string:
C:\Program Files\My Accessories\Winword.Exe
CAUSE
File associations are stored in the registry under HKEY_CLASS_ROOT, where
the executable name is actually stored under the key
HKEY_CLASSES_ROOT\<file Type>\shell\open\command = <Name of Executable>
By design, long file names stored in the registry should be enclosed in
quotation marks. Otherwise, the system is made to treat the rest of the
characters following the space as arguments.
In the example, the path to WinWord.Exe should be stored in the registry
as:
HKEY_CLASSES_ROOT\Word.Document.6\shell\open\command =
"C:\Program Files\My Accessories\Winword.Exe" /n
which does causes FindExecutable to return the expected string.
Note that this problem does not occur when the short path name is stored in
the registry, instead of the long file name. Again, taking the same example
to WinWord.exe, this should not be a problem if the short path name
"C:\Progra~1\MYACCE~1\WINWORD.EXE" is stored in the registry instead of the
LFN version.
RESOLUTION
In some situations, applications do not have control over what gets stored
in the registry. It may be the associated application's setup program that
wrote the incorrect LFN string (without quotation marks) to the registry.
Any application that would then call FindExecutable() on this associated
application will run into this problem.
One workaround to this problem might be to parse the string returned and
replace the \0 character with a space. Stepping through a debugger, after
FindExecutable() returns, you will quickly find that although the space has
been replaced with the NULL character (\0), the rest of the string is left
intact, so simply reverting the \0 character back to a space gives the
expected string.
STATUS
This behavior is by design.
| Modification Type: | Minor | Last Reviewed: | 7/11/2005 |
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| Keywords: | kbprb KB140724 |
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