 Boaz Brickner
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a5ddc3e3cd
|
Support importing C++ _Nonnull pointers as function parameters or return values (#5773)
We avoid using canonical type before knowing it's not a pointer because
we need the nullability attribute.
No support for pointers to pointers, yet.
C++ Interop Demo:
```c++
// hello_world.h
auto hello_world_param(int* _Nonnull i) -> void;
auto hello_world_return() -> int* _Nonnull;
```
```c++
// hello_world.cpp
#include "hello_world.h"
#include <cstdio>
auto hello_world_param(int* _Nonnull i) -> void {
printf("hello_world: %d\n", *i);
}
static int x = 5;
auto hello_world_return() -> int* _Nonnull { return &x; }
```
```carbon
// main.carbon
library "Main";
import Core library "io";
import Cpp library "hello_world.h";
fn Run() -> i32 {
var i: i32 = 10;
Cpp.hello_world_param(&i);
let p: i32* = Cpp.hello_world_return();
Core.Print(*p);
return 0;
}
```
```shell
$ clang -c hello_world.cpp
$ ./bazel-bin/toolchain/install/prefix_root/bin/carbon compile main.carbon
$ ./bazel-bin/toolchain/install/prefix_root/bin/carbon link hello_world.o main.o --output=demo
$ ./demo
hello_world: 10
5
```
Part of #5772.
|
2025-07-10 08:00:37 +00:00 |
|
Jon Ross-Perkins