Special Preprocessor Directives #error Directive The #error directive allows the preprocessor to output an error message during the compilation process and stop compilation. This is very useful for forcing developers to check the code when certain conditions are not met. For example: #include <iostream> #define USE_FEATURE_X 0 int main() { #if USE_FEATURE_X // Code using … Read more
In C++, to avoid the overhead caused by function calls (mainly parameter stack pushing, jumping, returning, etc.), one can use the inline function mechanism (<span>inline</span>) to directly replace the function in the calling place during the compilation phase, similar to macro expansion in C language, but safer and more controllable than macro functions. Below, we … Read more
The ## operator in C++ macros is known as the token pasting or token concatenation operator. It is used within macro definitions to concatenate two tokens into a single token when the macro is expanded. This operator is particularly useful for creating variable names, function names, or other identifiers dynamically during preprocessing. Syntax #define CONCATENATE(token1, … Read more