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Diffstat (limited to 'book/src/by-example/tips.md')
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diff --git a/book/src/by-example/tips.md b/book/src/by-example/tips.md index c163328..5057c80 100644 --- a/book/src/by-example/tips.md +++ b/book/src/by-example/tips.md @@ -20,6 +20,20 @@ rewrite code. If you consistently use `lock`s to access the data behind shared resources then your code will continue to compile when you change the priority of tasks. +## Conditional compilation + +You can use conditional compilation (`#[cfg]`) on resources (`static [mut]` +items) and tasks (`fn` items). The effect of using `#[cfg]` attributes is that +the resource / task will *not* be injected into the prelude of tasks that use +them (see `resources`, `spawn` and `schedule`) if the condition doesn't hold. + +The example below logs a message whenever the `foo` task is spawned, but only if +the program has been compiled using the `dev` profile. + +``` rust +{{#include ../../../examples/cfg.rs}} +``` + ## Running tasks from RAM The main goal of moving the specification of RTFM applications to attributes in |