BUG: GetGlyphOutline Causes Fatal Exception in Chinese, Japanese, and Korean Windows NT 4.0 (230747)

RESOLUTION

To work around the problem, always call the GetGlyphOutline function on Chinese, Japanese, and Korean versions of Windows NT with an identity matrix for the last parameter. Using an identity matrix avoids the code path in the operating system that causes the fatal exception.

A formal identity matrix contains only zeros and ones. Such a matrix can be initialized by using the following code snippet:

// Make an identity matrix
memset(&mat, 0, sizeof(mat));
mat.eM11.value = 1;
mat.eM12.value = 0;
mat.eM21.value = 0;
mat.eM22.value = 1;
				

Note that this snippet of code creates a true identity matrix. Any other method of initializing an identity matrix may produce a matrix definition with values other than zeros and ones.

In particular, a floating point conversion to the FIXED data type may introduce a nonzero value into the fract member of the FIXED structure. A FIXED structure with a nonzero fract component does not form a true identity and will cause the fatal exception to occur.

The problem has been fixed on Windows NT Far East Service Pack 5. Therefore, a matrix other than an identity matrix can be used if the Service Pack level is Service Pack 5 or later.