definedMACRO
definedMACRO is not a formal language feature with a fixed definition, but a term used to describe the practice of using preprocessor macros to detect whether another macro is defined. In languages with a C-style preprocessor, this detection is performed with the defined operator in conditional compilation directives.
The most common syntax uses #if defined(MACRO) or its equivalent #ifdef MACRO. These checks evaluate at compile
Use cases for definedMACRO patterns include platform-specific optimizations, feature toggles, and enabling or disabling support for
Limitations include that the defined operator is a preprocessor construct and only reflects the state of macros
See also: C preprocessor, conditional compilation, macro definitions, feature detection.