http: Avoid undefined behavior in va_arg conversion #34
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Subtracting a null pointer is undefined behavior according to Clang 13 (-Wnull-pointer-subtraction). Avoid this by casting to intptr_t instead. Request macros (e.g. OP_GET_SERVER_INFO) already do a simple cast `((char*)_request)` rather than addition with null pointer `(_request+(char*)NULL)` so nothing needs to be changed on that end.
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Compiling under Clang 13 with -Wextra resulted in the following warning:
It seems subtracting a null pointer is undefined behavior, which we can avoid by casting to intptr_t instead.
Request macros (e.g. OP_GET_SERVER_INFO) already do a simple cast
((char*)_request)rather than addition with null pointer(_request+(char*)NULL)so nothing needs to be changed on that end.