The _Pragma preprocessing operator
The unary operator _Pragma, which is a C99 feature,
allows a preprocessor macro to be contained in a pragma directive.
The string literal is destringized and tokenized. The resulting
sequence of tokens is processed as if it appeared in a pragma directive.
For example:
_Pragma ( "pack(full)" )#pragma pack(full)
Beginning of C++0x only.
In C++0x, the _Pragma operator feature of the
C99 preprocessor is adopted to provide a common preprocessor interface
for C and C++ compilers. The _Pragma operator is
an alternative method of specifying the #pragma directive.
For more information, see C99 preprocessor features adopted in C++11 (C++11).
End of C++0x only.