Trait dlopen::symbor::SymBorApi

pub trait SymBorApi<'a> where
    Self: Sized, {
    unsafe fn load(lib: &'a Library) -> Result<Self, Error>;
}

Trait for automatic loading of symbols from library.

This trait is intended to be used together with the derive macro. To use it you need to define a structure, create several fields that implement the FromRawResult trait and then simply use the automatically generated load(&Library) function to load all symbols from previously opened library.

#[macro_use]
extern crate dlopen_derive;
extern crate dlopen;
extern crate libc;
use dlopen::symbor::{Library, Symbol, SymBorApi, PtrOrNull, RefMut, PtrOrNullMut};
use libc::{c_double, c_char};

#[derive(SymBorApi)]
struct Example<'a> {
    pub simple_fun: Symbol<'a, unsafe extern "C" fn()>,
    pub complex_fun: Symbol<'a, unsafe extern "C" fn(c_double)->c_double>,
    pub optional_fun: Option<Symbol<'a, unsafe extern "C" fn()>>,
    pub nullable_ptr: PtrOrNullMut<'a, c_char>,
    pub mut_ref_i32: Symbol<'a, &'a mut i32>,
    #[dlopen_name="mut_ref_i32"]
    pub the_same_mut_ref_i32: RefMut<'a, i32>,
    pub not_nullable_ptr: Symbol<'a, * mut c_double>
}

fn main(){
    let lib = Library::open("example.dll").expect("Could not open library");
    let mut api = unsafe{Example::load(&lib)}.expect("Could not load symbols");
    unsafe{(api.simple_fun)()};
    let _ = unsafe{(api.complex_fun)(1.0)};
    match api.optional_fun {
        Some(fun) => unsafe {fun()},
        None => println!("Optional function could not be loaded"),
    };
    if api.nullable_ptr.is_null(){
        println!("Library has a null symbol");
    }
    //while Symbol is good for everything, RefMut requires one less dereference to use
    **api.mut_ref_i32 =34;
    *api.the_same_mut_ref_i32 =35;
    unsafe{**api.not_nullable_ptr = 55.0};
    unsafe{**api.nullable_ptr = 0};
}

Please notice several supported features:

• By default SymBorApi uses the field name to obtain a symbol from the library. You can override the symbol name using the dlopen_name attribute.
• All kind of objects from the symbor module implement the Deref or DerefMut trait. This means that you can use them as if you would use primitive types that they wrap.
• You can obtain optional symbols. This is very useful when you are dealing with different versions of libraries and the new versions support more functions. If it is not possible to obtain the given symbol, the option is set to `None’, otherwise it contains the obtained symbol.
• Both Symbol and Ref or RefMut can be used to obtain references to statically allocated objects. But Ref and RefMut are just easier to use - they require less dereferences to access the final value. Actually they behave like a normal reference does, it just that they implement the FromRawResult interface that allows them to be used inside structures that implement the SymBorApi trait.

Required methods

unsafe fn load(lib: &'a Library) -> Result<Self, Error>

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Implementors

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