Slow Function Warning

This crate provides a procedural macro to inject timers into functions and print a warning if it takes longer than expected. It can be particularly useful for debugging performance issues during development.

Conditional Compilation

Timing functions can affect the performance of your application, so it's important to use conditional compilation to ensure that the timing code is only included when necessary.

debug_slow_function_warning // in debug mode
release_slow_function_warning // in release mode
slow_function_warning // in both debug and release mode

Usage

Installation

Add the following to your Cargo.toml:

[dependencies]
slow_function_warning = "0.1.0"

Basic Example

#[debug_slow_function_warning(1000ms)] // Warn if the function takes longer than 1000 milliseconds
fn example_function() {
    // Function implementation
}

Custom Message Example

#[debug_slow_function_warning(1s, println!("Function {function} took too long!"))] // Warn if the function takes longer than 1000 milliseconds with a custom message
fn example_function() {
    // Function implementation
}

Duration Syntax

You can specify the duration using numeric literals followed by a suffix:

ns for nanoseconds
ms for milliseconds
s for seconds
m for minutes
h for hours
d for days

Available Variables

module: String - The name of the module
function: String - The name of the function
elapsed: Duration - The elapsed time
nanos: u64 - The elapsed time in nanoseconds
ns: u64 - The elapsed time in nanoseconds
millis: u64 - The elapsed time in milliseconds
ms: u64 - The elapsed time in milliseconds
secs: u64 - The elapsed time in seconds
s: u64 - The elapsed time in seconds

slow_function_warning 0.1.0