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Use println to print hello world

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Philipp Oppermann
2015-10-23 01:43:05 +02:00
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_drafts/printing-to-screen.md
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@@ -364,6 +364,22 @@ pub fn clear_screen() {
} }
} }
``` ```
### Hello World using `println`
To use `println` in `lib.rs`, we need to import the macros of the VGA buffer module first. Therefore we add a `#[macro_use]` attribute to the module declaration:
```rust
#[macro_use]
mod vga_buffer;
#[no_mangle]
pub extern fn rust_main() {
// ATTENTION: we have a very small stack and no guard page
println!("Hello World{}", "!");
loop{}
}
```
Since we imported the macros at crate level, they are available in all modules and thus provide an easy and safe interface to the VGA buffer.
## What's next? ## What's next?
Soon we will tackle virtual memory management and map the kernel sections correctly. This will cause many strange bugs and boot loops. To understand what's going on a real debugger is indispensable. In the [next post] we will setup [GDB] to work with QEMU. Soon we will tackle virtual memory management and map the kernel sections correctly. This will cause many strange bugs and boot loops. To understand what's going on a real debugger is indispensable. In the [next post] we will setup [GDB] to work with QEMU.