C++ API with datatype with #pragma pack () causes exception

If I have a variable defined with #pragma pack (1), Matlab crashes with an exception as soon as I try to define the variable in the use the Matlab workspace via

testStruct = clib.<libraryName>.testStruct;

Without the #pragma it works just fine. Has anyone gotten this pragma to work? The existing C++ code I am working with has many of these pragmas so I would prefer to keep them as is if possible.

#pragma pack (1)
struct testStruct{
	double a;
	char   c;
	double b;
};