Target

Limits a declaration to a specific operating system. The compiler ignores the annotated item when building for any other target.

Syntax

@[Target("Linux")]
func Do() {
    // Implementation
}

Valid operating system strings:

Attribute	Operating system
@[Target("BSD")]	FreeBSD / OpenBSD / NetBSD / DragonFly BSD
@[Target("Illumos")]	Illumos / OmniOS
@[Target("Linux")]	Linux
@[Target("MacOS")]	macOS
@[Target("Windows")]	Windows

Examples

Platform-specific imports

@[Target("Linux")]
import Linux::LinuxHelper;

@[Target("Windows")]
import Windows::WinHelper;

Only the import that matches the current build target is resolved. The others are silently skipped, so their packages do not need to be listed in [Dependencies] for all platforms — only under the corresponding [Dependencies.Target.<OS>] section.

Platform-specific functions

These attributes enable the creation of multi-platform packages with a specified interface.

@[Target("Linux")]
func CreateFile(filename: String) {
    // Platform-specific implementation for Linux
}

@[Target("MacOS")]
func CreateFile(filename: String) {
    // Platform-specific implementation for macOS
}

@[Target("Windows")]
func CreateFile(filename: String) {
    // Platform-specific implementation for Windows
}

Multiple attributes may be stacked before a single declaration.

@[Target("Windows")]
@[Import(lib: "User32.dll")]
extern func MessageBoxA(
    hwnd: *opaque,
    text: *char8,
    caption: *char8,
    type: uint32) -> int32;

The compiler will use the functions only for the current target.

@[Target("Linux")]
@[Import(lib: "librt.so")]
extern func clock_gettime(clockid: int32, tp: *opaque) -> int32;

@[Target("Windows")]
@[Import(lib: "Kernel32.dll")]
extern func GetTickCount64() -> uint64;