xmake-objc

Building Objective-C / Objective-C++ with Xmake

Objective-C (.m) and Objective-C++ (.mm) are first-class in xmake. Primary use case: macOS / iOS / tvOS apps, Cocoa frameworks, and mixed C++ / Objective-C projects.

1. Minimal Objective-C project

add_rules("mode.debug", "mode.release")

target("hello")
    set_kind("binary")
    add_files("src/*.m")
    add_frameworks("Foundation")

// src/main.m
#import <Foundation/Foundation.h>
int main() {
    @autoreleasepool {
        NSLog(@"hello from xmake");
    }
    return 0;
}

2. Objective-C++ (mixing with C++)

Use .mm extension and set the C++ language level:

target("app")
    set_kind("binary")
    set_languages("c++17")
    add_files("src/*.mm", "src/*.cpp")
    add_frameworks("Foundation", "AppKit")

.mm files compile with the Objective-C++ front-end — you can freely mix @interface/@implementation with C++ classes and templates.

3. Frameworks

target("app")
    add_frameworks("Foundation", "Cocoa", "AppKit", "Metal", "MetalKit", "CoreGraphics")
    add_frameworkdirs("/Library/Frameworks", "$(projectdir)/vendor/frameworks")

• add_frameworks(...) — system or user frameworks (equivalent of -framework <name>).
• add_frameworkdirs(...) — additional search paths for non-system frameworks.

4. Flags

target("app")
    add_mflags("-fobjc-arc")                    -- Objective-C flag (.m)
    add_mxxflags("-fobjc-arc")                  -- Objective-C++ flag (.mm)

add_mflags / add_mxxflags target .m / .mm respectively; add_cxflags still flows through to both.

ARC is the default in modern Xcode; include -fobjc-arc explicitly if you want to be sure.

5. Apple platform targets

xmake f -p macosx  -a arm64
xmake f -p iphoneos -a arm64
xmake f -p iphonesimulator -a arm64
xmake f -p appletvos -a arm64
xmake f -p watchos -a arm64
xmake

Pin SDK version and minimum deployment:

xmake f -p iphoneos --xcode_sdkver=17.2 --target_minver=14.0

6. Application bundle

For a proper .app bundle on macOS:

target("myapp")
    add_rules("xcode.application")               -- produces .app
    add_files("src/*.m", "res/*.storyboard", "res/*.xcassets")
    add_files("res/Info.plist")
    add_frameworks("Foundation", "AppKit")

iOS app:

target("myapp")
    add_rules("xcode.application")
    set_plat("iphoneos")
    add_files("src/*.m", "res/Info.plist")
    add_frameworks("Foundation", "UIKit")

xcode.application is a built-in rule that produces a proper bundle with Info.plist, code signing hooks, etc.

7. Consuming Objective-C from Swift

See xmake-swift — Swift interop picks up Objective-C headers via set_values("swift.interop", "objc").

8. Pure C ↔ Objective-C

Objective-C is a strict superset of C, so a .m file can #include <stdio.h> freely. Pure C headers compile inside .m/.mm files without extra flags.

Pitfalls

• .mm without set_languages("c++XX"). Defaults to C++98 which is almost never what you want. Set it explicitly.
• System frameworks vs SDK version. add_frameworks("SwiftUI") fails on old macOS SDKs. Pin with --xcode_sdkver= or gate with is_plat + minver.
• Missing -fobjc-arc on old code. Pre-ARC code uses retain/release; modern code uses ARC. Don't mix arbitrarily.
• Info.plist missing from bundle. xcode.application needs an Info.plist in add_files or it produces a broken bundle.
• Cross-compile to iOS without Xcode. Only possible on macOS — iOS SDK is Xcode-only.

When to branch out

• Apple-platform toolchain / SDK → xmake-cross-compilation, xmake-toolchains
• Swift interop → xmake-swift
• Target basics → xmake-targets
• Packaging a .app bundle as .dmg / .ipa → xmake-xpack