[英]How to call a Rust struct's method from C using FFI?
我试图使用FFI从C程序调用公共函数(位于Rust结构的impl块内)。 调用常规pub fn
s并没有太多麻烦,但我试图从struct
的impl
块中调用pub fn
,而没有找到正确的语法来公开/调用它。 当然这是可能的,对吧?
#[repr(C)]
#[derive(Debug)]
pub struct MyStruct {
var: i32,
}
#[no_mangle]
pub extern "C" fn new() -> MyStruct {
MyStruct { var: 99 }
}
#[no_mangle]
impl MyStruct {
#[no_mangle]
pub extern "C" fn print_hellow(&self) {
println!("{}", self.var);
}
}
typedef struct MyStruct
{
int var;
} MyStruct;
extern MyStruct new (void);
extern void print_hellow(MyStruct);
int main()
{
MyStruct instance1;
MyStruct instance2 = new ();
printf("Instance1 var:%d\n", instance1.var);
/// successfully prints the uninitialized 'var'
printf("Instance2 var:%d\n", instance2.var);
/// successfully prints the initialized 'var'
print_hellow(instance1);
/// fails to link during compilation
return 0;
}
不,这是不可能的。 您需要为要访问的每个方法编写填充函数:
#[no_mangle]
pub unsafe extern "C" fn my_struct_print_hellow(me: *const MyStruct) {
let me = &*me;
me.print_hellow();
}
也可以看看:
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