external.md

External Declarations

The external keyword declares blocks of functions, structs and global variables that are implemented externally. Use compiler attributes and compiler settings to control this.

External Structs

Structs declared in external blocks follow the layout rules of the target language.

External Function Example

All parameters and returns from C external functions must be one of:

• A simple numeric type (i.e. int32, float etc.)
• An external struct
• A pointer to one of the above

#Link("libc")
external // by default, changes to 'C' ABI
{
    public fn function() -> int;
}

TODO: switch to a less generic attribute name than Link

Exporting Example

Exporting allows functions to be called from other languages.

#export // tells it to make this function visible externally, and not mangle the name, by default, changes to 'C' ABI
publish fn something() -> void
{
    // implementation
}

#export("NewName") // export as the given name
#calling_convention(.Fast) // should take an enum value, can also be applied to external block
publish fn something2() -> void
{
    // implementation
}