> For the complete documentation index, see [llms.txt](https://trizen.gitbook.io/perl6-rosettacode/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://trizen.gitbook.io/perl6-rosettacode/programming_tasks/c/call_a_function_in_a_shared_library.md).

# Call a function in a shared library

```perl
use NativeCall;

sub XOpenDisplay(Str $s --> int64) is native('X11') {*}
sub XCloseDisplay(int64 $i --> int32) is native('X11') {*}

if try my $d = XOpenDisplay ":0.0" {
    say "ID = $d";
    XCloseDisplay($d);
}
else {
    say "No X11 library!";
    say "Use this window instead --> ⬜";
}
```

#### Output:

```
ID = 94722089782960
```