BUG: GetKerningPairs Sometimes Fails on Win32s 1.2 and 1.25a (125872)
The information in this article applies to:
- Microsoft Win32 Application Programming Interface (API), when used with:
This article was previously published under Q125872
1.20 1.25a
WINDOWS
kbgraphic kbbuglist
SYMPTOMS
GetKerningPairs will sometimes fail on Win32s version 1.2 causing the
32-bit application to exit mysteriously. The problem may only occur once in
a while with many successful runs interrupted by a single unsuccessful run.
CAUSE
The thunking layer for GetKerningPairs contains a bug in the code that
allocates a temporary buffer passed to the 16-bit version of
GetKerningPairs. The errant code executes whenever the number of kerning
pairs requested is equal to or less than 128. Requesting GetKerningPairs to
return 129 or more kerning pairs forces the thunking layer to use an
alternative buffer allocation method.
RESOLUTION
To work around the problem, ensure that the number of kerning pairs
requested from GetKerningPairs is greater than 128.
Typically, kerning pairs are retrieved with two calls to GetKerningPairs.
The first call retrieves the number of kerning pairs available. A buffer is
allocated based on the number of pairs returned. Then the second call to
GetKerningPairs retrieves the kerning pairs into the buffer.
To avoid the bug in GetKerningPairs, follow these steps:
- Retrieve the number of kerning pairs available from GetKerningPairs.
- Check that this value is greater than 128. If it is less than or
equal to 128, reset the variable to an arbitrary value greater than
128 -- like 129.
- Use the new value to allocate the buffer of KERNINGPAIRS and pass
this new value with the buffer to the second GetKerningPairs call.
STATUSMicrosoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.
| Modification Type: | Minor | Last Reviewed: | 3/7/2005 |
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| Keywords: | kbbug kbpending KB125872 |
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