W3cubDocs

/GCC 7 CPP

3.7 Predefined Macros

Several object-like macros are predefined; you use them without supplying their definitions. They fall into three classes: standard, common, and system-specific.

In C++, there is a fourth category, the named operators. They act like predefined macros, but you cannot undefine them.

© Free Software Foundation
Licensed under the GNU Free Documentation License, Version 1.3.
https://gcc.gnu.org/onlinedocs/gcc-7.1.0/cpp/Predefined-Macros.html