C51 provides you with predefined constants to use in preprocessor directives and C code for more portable programs. The following table lists and describes each one.
| Constant |
Description |
| _ _FILE_ _ |
The name of the file being compiled. |
| _ _LINE_ _ |
The current line number in the file being compiled. |
| _ _TIME_ _ |
The time when the compilation was started. |
| _ _DATE_ _ |
The date when the compilation was started. |
| _ _STDC_ _ |
The full conformance with the ANSI C Standard. It is always defined with the value 1. |
| _ _C51_ _ |
The version number of the C51 compiler (e.g., 300 for version 3.00). |
| _ _MODEL_ _ |
The memory model selected (0 for small, 1 for compact, 2 for large). |