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[Page 1279 (continued)]

F.8. Predefined Symbolic Constants

There are six predefined symbolic constants (Fig. F.1). The identifiers for each of these begin and (and, except for __cplusplus, end) with two underscores. These identifiers and the defined preprocessor operator (Section F.5) cannot be used in #define or #undef directives.

Figure F.1. The predefined symbolic constants.

Symbolic constant



The line number of the current source code line (an integer constant).


The presumed name of the source file (a string).


The date the source file is compiled (a string of the form "Mmm dd yyyy" such as "Aug 19 2002").


Indicates whether the program conforms to the ANSI/ISO C standard. Contains value 1 if there is full conformance and is undefined otherwise.


The time the source file is compiled (a string literal of the form "hh:mm:ss").


Contains the value 199711L (the date the ISO C++ standard was approved) if the file is being compiled by a C++ compiler, undefined otherwise. Allows a file to be set up to be compiled as either C or C++.

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