Can the program I compiled with /Qregcall call functions in system DLL?
Calling Conventions of the system DLL is __cdecl or __stdcall.
Can the program compiled without /Qregcall call functions compiled with /Qregcall?
Please see https://software.intel.com/en-us/cpp-compiler-developer-guide-and-reference-regcall-qregcall for details.
For more complete information about compiler optimizations, see our Optimization Notice.