SWIG/Examples/go/constants/
Wrapping C Constants
When SWIG encounters C preprocessor macros and C declarations that
look like constants, it creates a Go constant with an identical value.
Click here to see a SWIG interface with some
constant declarations in it.
Accessing Constants from Go
Click here for
the section on constants in the SWIG and Go documentation.
Click here to see a Go program that prints out
the values of the constants contained in the above file.
Key points
- All names are capitalized to make them visible.
- The values of preprocessor macros are converted into Go constants.
- C string literals such as "Hello World" are converted into Go strings.
- Macros that are not fully defined are simply ignored. For example:
#define EXTERN extern
is ignored because SWIG has no idea what type of variable this would be.
- Expressions are allowed provided that all of their components are
defined. Otherwise, the constant is ignored.
- Certain C declarations involving 'const' are also turned into Go
constants.
- The constants that appear in a SWIG interface file do not have to
appear in any sort of matching C source file since the creation of a
constant does not require linkage to a stored value (i.e., a value
held in a C global variable or memory location).