# tracing::subscriber::set_global_default - Rust
API documentation for the Rust `set_global_default` fn in crate `tracing`.
Keywords: rust, rustlang, rust-lang, set_global_default

# Function tracing::subscriber::set_global_default [−] [src]

    pub fn set_global_default<S>(subscriber: S) -> Result<(), SetGlobalDefaultError> where
        S: Subscriber + Send + Sync + 'static,

Sets this subscriber as the global default for the duration of the entire program. Will be used as a fallback if no thread-local subscriber has been set in a thread (using `with_default`.)

Can only be set once; subsequent attempts to set the global default will fail. Returns whether the initialization was successful.

Note: Libraries should NOT call `set_global_default()`! That will cause conflicts when executables try to set them later.