startup 0.0.1

Tiny (no dependency, no proc macro) way to run some code before main.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

# `startup`: Run Rust code "before main"

[![Docs](https://docs.rs/startup/badge.svg)](https://docs.rs/startup)
[![Latest Version](https://img.shields.io/crates/v/startup.svg)](https://crates.io/crates/startup)

Tiny (no-dependency, no proc macro) way to run some code before main (or when your dynamic library is loaded in the case of code loaded via dlopen). This is similar to the GNU C extension `__attribute__((constructor))`, or the behavior of static constructors from C++.

## Usage

```rust
startup::on_startup! {
    // Note: not all of the rust stdlib may be supported before main.
    println!("I'm running before main");
}
fn main() {
    println!("I'm inside main");
}
```

Prints:

```text
I'm running before main.
I'm inside main.
```

## Comparison with `ctor`

This crate is the moral equivalent to the [`ctor`](https://crates.io/crates/ctor) crate, although the API is completely different. The main reasons for it's existence are:

- Much faster to compile — no proc macros / syn / quote.
- More obviously safe. No support for `#[ctor]` on statics, no `#[dtor]` equivalent, and avoids a number of issues I filed with `ctor` in the past...
- Handle untested unix platforms by assuming they support *at least* the `.ctors` section. This is in line with what clang seems to do when compiling C++ static constructors. This means we should expect to have better platform support.