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In many situations, you don't really need conditional compilation; you just need conditional behavior that you can switch on and off. For that, you can use an environment variable. This has the huge advantage that you don't actually have to recompile.

You can set the environment variable, and easily switch it on or off, in the scheme editor:

You can retrieve the environment variable with NSProcessInfo:

    let dic = NSProcessInfo.processInfo().environment
    if dic["TRIPLE"] != nil {
        // ... do secret stuff here ...
    }

Here's a real-life example. My app runs only on the device, because it uses the music library, which doesn't exist on the Simulator. How, then, to take screen shots on the Simulator for devices I don't own? Without those screen shots, I can't submit to the AppStore.

I need fake data and a different way of processing it. I have two environment variables: one which, when switched on, tells the app to generate the fake data from the real data while running on my device; the other which, when switched on, uses the fake data (not the missing music library) while running on the Simulator. Switching each of those special modes on / off is easy thanks to environment variable checkboxes in the Scheme editor. And the bonus is that I can't accidentally use either them in my App Store build, because archiving has no environment variables.

In many situations, you don't really need conditional compilation; you just need conditional behavior that you can switch on and off. For that, you can use an environment variable. This has the huge advantage that you don't actually have to recompile.

You can set the environment variable, and easily switch it on or off, in the scheme editor:

You can retrieve the environment variable with NSProcessInfo:

    let dic = NSProcessInfo.processInfo().environment
    if dic["TRIPLE"] != nil {
        // ... do secret stuff here ...
    }

Here's a real-life example. My app runs only on the device, because it uses the music library, which doesn't exist on the Simulator. How, then, to take screen shots on the Simulator for devices I don't own? Without those screen shots, I can't submit to the AppStore.

I need fake data and a different way of processing it. I have two environment variables: one which, when switched on, tells the app to generate the fake data from the real data while running on my device; the other which, when switched on, uses the fake data (not the missing music library) while running on the Simulator. Switching each of those special modes on / off is easy thanks to environment variable checkboxes in the Scheme editor. And the bonus is that I can't accidentally use them in my App Store build, because archiving has no environment variables.

In many situations, you don't really need conditional compilation; you just need conditional behavior that you can switch on and off. For that, you can use an environment variable. This has the huge advantage that you don't actually have to recompile.

You can set the environment variable, and easily switch it on or off, in the scheme editor:

You can retrieve the environment variable with NSProcessInfo:

    let dic = NSProcessInfo.processInfo().environment
    if dic["TRIPLE"] != nil {
        // ... do secret stuff here ...
    }

In many situations, you don't really need conditional compilation; you just need conditional behavior that you can switch on and off. For that, you can use an environment variable. This has the huge advantage that you don't actually have to recompile.

You can set the environment variable, and easily switch it on or off, in the scheme editor:

You can retrieve the environment variable with NSProcessInfo:

    let dic = NSProcessInfo.processInfo().environment
    if dic["TRIPLE"] != nil {
        // ... do secret stuff here ...
    }

Here's a real-life example. My app runs only on the device, because it uses the music library, which doesn't exist on the Simulator. How, then, to take screen shots on the Simulator for devices I don't own? Without those screen shots, I can't submit to the AppStore.

I need fake data and a different way of processing it. I have two environment variables: one which, when switched on, tells the app to generate the fake data from the real data while running on my device; the other which, when switched on, uses the fake data (not the missing music library) while running on the Simulator. Switching each of those special modes on / off is easy thanks to environment variable checkboxes in the Scheme editor. And the bonus is that I can't accidentally use either them in my App Store build, because archiving has no environment variables.

In many situations, you don't really need conditional compilation; you just need conditional behavior that you can switch on and off. For that, you can use an environment variable. This has the huge advantage that you don't actually have to recompile.

You can set the environment variable, and easily switch it on or off, in the scheme editor:

You can retrieve the environment variable with NSProcessInfo:

    let dic = NSProcessInfo.processInfo().environment
    if dic["TRIPLE"] {
        // ... do secret stuff here ...
    }

In many situations, you don't really need conditional compilation; you just need conditional behavior that you can switch on and off. For that, you can use an environment variable. This has the huge advantage that you don't actually have to recompile.

You can set the environment variable, and easily switch it on or off, in the scheme editor:

You can retrieve the environment variable with NSProcessInfo:

    let dic = NSProcessInfo.processInfo().environment
    if dic["TRIPLE"] != nil {
        // ... do secret stuff here ...
    }