Fix configure failure on 32-bit MSVC. #64
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Windows libraries being checked (ws2_32, rpcrt4, iphlpapi) contain functions following stdcall convention. While on 64-bit platform it makes no difference, on 32-bit it does. For example, function WSAGetLastError is mangled by MSVC like "_WSAGetLastError@0". CMake checks if a function FUNC is present in a library by compiling a simple C source containing function definition "char FUNC()" and then calling it. Since stdcall functions are mangled in such a way that requires correct number of arguments (written after "@"), checking for a function with non-zero number of arguments will fail. That is why we check for functions which have zero arguments and we also force stdcall convention.
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Sep 11, 2015
Fix configure failure on 32-bit MSVC.
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Windows libraries being checked (ws2_32, rpcrt4, iphlpapi) contain functions following stdcall convention. While on 64-bit platform it makes no difference, on 32-bit it does. For example, function WSAGetLastError is mangled by MSVC like "_WSAGetLastError@0". CMake checks if a function FUNC is present in a library by compiling a simple C source containing function definition "char FUNC()" and then calling it. Since stdcall functions are mangled in such a way that requires correct number of arguments (written after "@"), checking for a function with non-zero number of arguments will fail.
That is why we check for functions which have zero arguments and we also force stdcall convention.