Add a #[start] attribute #5158
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A-attributes
Area: Attributes (`#[…]`, `#![…]`)
A-codegen
Area: Code generation
E-easy
Call for participation: Easy difficulty. Experience needed to fix: Not much. Good first issue.
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Apr 10, 2013
This implements #5158. Currently it takes the command line args and the crate map. Since it doesn't take a `main` function pointer, you can't actually start the runtime easily, but that seems to be a shim to allow the current `rust_start` function to call into main. However, you can do an end-run round the io library and do this: ```rust use core::libc::{write, c_int, c_void, size_t, STDOUT_FILENO}; #[start] fn my_start(_argc:int, _argv: **u8, _crate_map: *u8) -> int { do str::as_buf("Hello World!\n") |s,len| { unsafe { write(STDOUT_FILENO, s as *c_void, len as size_t); } } return 0; } ``` Which is the most basic "Hello World" you can do in rust without starting up the runtime (though that has quite a lot to do with the fact that `core::io` uses `@` everywhere...)
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Apr 12, 2013
This implements #5158. Currently it takes the command line args and the crate map. Since it doesn't take a `main` function pointer, you can't actually start the runtime easily, but that seems to be a shim to allow the current `rust_start` function to call into main. However, you can do an end-run round the io library and do this: ```rust use core::libc::{write, c_int, c_void, size_t, STDOUT_FILENO}; #[start] fn my_start(_argc:int, _argv: **u8, _crate_map: *u8) -> int { do str::as_buf("Hello World!\n") |s,len| { unsafe { write(STDOUT_FILENO, s as *c_void, len as size_t); } } return 0; } ``` Which is the most basic "Hello World" you can do in rust without starting up the runtime (though that has quite a lot to do with the fact that `core::io` uses `@` everywhere...)
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May 2, 2020
Impl DefaultCallbacks on our side cc rust-lang#69059 (comment) changelog: none
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This would let you override the 'start' lang item to create a program entry point that does not use the scheduler. There's some question about whether this entry point would have the same signature as the lang item or not - there may be use cases for one that accepts the current arguments (like
crate_map) and one that has no arguments.The text was updated successfully, but these errors were encountered: