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Defines a macro name.





Is the name of the macro to be defined.


Is an optional list of comma-separated macro parameters. By appending a macro parameter list to the macro name, you can define function-style macros.

The parameter list must be enclosed in parentheses. When specifying multiple parameters, do not include spaces between commas and parameter names in the list.


Parentheses might require escaping on UNIX systems.


Is an optional macro definition.

If =def is omitted, the compiler defines name as the value 1.

To include characters recognized as tokens on the command line, enclose the macro definition in double quotes.


Specifying -Dname has the same effect as placing the text #define name at the head of each source file.


Specifying this option:

-DMAX(X,Y)="((X > Y) ? X : Y)"

is equivalent to defining the macro:

#define MAX(X, Y) ((X > Y) ? X : Y)

at the head of each source file.