Parameters in dynamic libraries cannot be modified through macro definitions or global variables in header files

It is expected that the dynamic library provided to the user, through the macros or global variables defined in the header file of the library, modify the parameters used in the execution of logic in the dynamic library, and find that this path is not feasible. Once the dynamic library has been generated, modify the headerThe macro definitions or global variables in the file will not modify the variables in the dynamic library, and these variables still use the values ​​defined when the dynamic library is generated.

Header file definition:

#pragma once#ifdef TESTLIBRARY_EXPORTS#define TESTLIBRARY_API __declspec(dllexport)#else#define TESTLIBRARY_API __declspec(dllimport)#endif#define TWO_CHANNEL_MAX_POWER_DIFF 0.5 // Two channel maximum average powerdifference// or using external variableextern twoChMaxPwrDiff = 0.5;

Once the dll is generated using the above header file, TWO_CHANNEL_MAX_POWER_DIFF and twoChMaxPwrDiff have been determined, this header file and dll are provided to the user, and the user modifies theMacro or global variable definitions will not take effect, and the values ​​used are still those defined when the dll was generated.

The solution to this problem is to provide a new interface function, which the user calls to modify the parameters in the dll, which is the same logic as the way of passing parameters.

Header file

extern "C" TESTLIBRARY_API void __cdecl SetTwoChMaxPwrDiff(doublespan> diff);

Source file

static double twoChMaxPwrDiff = 0; //variable definitionspan>void SetTwoChMaxPwrDiff(double diff) {twoChMaxPwrDiff = diff;}