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Diffstat (limited to 'src/macros/select.rs')
| -rw-r--r-- | src/macros/select.rs | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/src/macros/select.rs b/src/macros/select.rs index 7ba04a0..31c9b3a 100644 --- a/src/macros/select.rs +++ b/src/macros/select.rs @@ -131,6 +131,13 @@ /// correctly even if it is restarted while waiting at an `.await`, then it is /// cancellation safe. /// +/// Cancellation safety can be defined in the following way: If you have a +/// future that has not yet completed, then it must be a no-op to drop that +/// future and recreate it. This definition is motivated by the situation where +/// a `select!` is used in a loop. Without this guarantee, you would lose your +/// progress when another branch completes and you restart the `select!` by +/// going around the loop. +/// /// Be aware that cancelling something that is not cancellation safe is not /// necessarily wrong. For example, if you are cancelling a task because the /// application is shutting down, then you probably don't care that partially |