C language: Common predefined macros

Common predefined macros
 
All compilers that follow the iso c Standard must define the following macros. The macro names start with two underscores and end with two underscores.
 
1. _ DATE __
"Alternative text" is a string literal with a compilation date in the format of "mm dd yyyy" (for example, "Mar 19 2006 "). If the date is less than 10 days, place a space character in front of the day.
 
2. _ FILE __
The literal value of this string contains the name of the current source code file.
 
3. _ LINE __
An integer constant whose value is the current source code LINE number (containing the LINE code indicated by _ LINE _ macro), starting from the file header.
_ LINE _ and _ FILE _ are convenient for printing debugging information.
Printf ("line = % d \ n", _ LINE __);
Printf ("file = % s \ n", _ FILE __);
 
4. _ TIME __
The literal value of this string contains the Compilation Time in the format of "hh: mm: ss" (example: "08:00:59 ").
5. _ STDC __
Integer constant 1, indicating that the compiler complies with the ISOC standard.



From the happy life of codoon