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Is it possible to have in C something like:
#define MACRO_EX 333
#define MACRO_EX(X,Y) ((X) < (Y) ? : (X) : (Y))
Can they coexist?
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3.1 Object-like Macros An object-like macro is a simple identifier which will be replaced by a code fragment. It is called object-like because it looks like a data object in code that uses it. They are most commonly used to give symbolic names to numeric constants. foo = (char *) malloc (1024);
Function-like macro definition: An identifier followed by a parameter list in parentheses and the replacement tokens. The parameters are imbedded in the replacement code. White space cannot separate the identifier (which is the name of the macro) and the left parenthesis of the parameter list.
A macro is defined with the pre-processor directive. Macros are pre-processed which means that all the macros would be processed before your program compiles. However, functions are not preprocessed but compiled.
A macro is a piece of code in a program that is replaced by the value of the macro. Macro is defined by #define directive. Whenever a macro name is encountered by the compiler, it replaces the name with the definition of the macro. Macro definitions need not be terminated by a semi-colon(;).
There are two types of macros: Object-like Macros. Function-like Macros.
Speed versus size The main benefit of using macros is faster execution time. During preprocessing, a macro is expanded (replaced by its definition) inline each time it is used. A function definition occurs only once regardless of how many times it is called.
The C standard says (ISO/IEC 9899:1999, §6.10.3, 2):
An identifier currently defined as an object-like macro shall not be redefined by another #define preprocessing directive unless the second definition is an object-like macro definition and the two replacement lists are identical. Likewise, an identifier currently defined as a function-like macro shall not be redefined by another #define preprocessing directive unless the second definition is a function-like macro definition that has the same number and spelling of parameters, and the two replacement lists are identical.
So the answer is no.
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