The _Pragma preprocessing operator

The unary operator _Pragma, allows a preprocessor macro to be contained in a pragma directive. 

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_Pragma operator syntax

>>-_Pragma--(--"--string_literal--"--)-------------------------><
The string_literal can be prefixed with L, making it a wide-string literal.
The string literal is destringized and tokenized. The resulting sequence of tokens is processed as if it appeared in a pragma directive. For example, the following two statements are equivalent:
_Pragma ( "pack(full)" )
#pragma pack(full)
Parent topic: Pragma directives