Attribute Macro export

#[export]

The export procedural macro facilitates FFI (Foreign Function Interface) conversion for a given function. It handles both input arguments and output types, converting them into a format suitable for FFI boundaries.

Syntax

The macro can be applied to any Rust function:

#[ferment_macro::export]
pub fn my_function(arg1: MyType1, arg2: MyType2) -> MyReturnType {
    // function implementation
}

Output

The macro will automatically generate additional FFI-compatible code around the annotated function. It converts the function into a form that can be easily invoked from C/C++ code.

Safety

This macro generates safety documentation specific to the function, covering the expectations and constraints of the FFI boundary.

Function Conversion

The macro processes the function’s input arguments and return type, performing necessary transformations like memory allocation/deallocation, pointer conversion, etc., to make them FFI-compatible.

Panics

• The macro will panic if any of the function’s argument types are not supported for conversion.
• The macro will also panic if the function’s return type is not supported for conversion.

Example

#[ferment_macro::export]
pub fn add(a: i32, b: i32) -> i32 {
    a + b
}

After applying the macro, the function can be safely invoked from C/C++ code.

Note

This macro is intended for internal use and should be used cautiously, understanding the risks associated with FFI calls.

See Also

Limitations

• The macro currently does not support Rust async functions.
• Nested data structures may not be fully supported.