The Rust Core Library
The Rust Core Library is the dependency-free1 foundation of The Rust Standard Library. It is the portable glue between the language and its libraries, defining the intrinsic and primitive building blocks of all Rust code. It links to no upstream libraries, no system libraries, and no libc.
The core library is minimal: it isn’t even aware of heap allocation, nor does it provide concurrency or I/O. These things require platform integration, and this library is platform-agnostic.
How to use the core library
Please note that all of these details are currently not considered stable.
This library is built on the assumption of a few existing symbols:
strlen- These are core memory routines which are often generated by LLVM. Additionally, this library can make explicit calls to these functions. Their signatures are the same as found in C. These functions are often provided by the system libc, but can also be provided by the compiler-builtins crate.
rust_begin_panic- This function takes four arguments, a
&'static str, and two
u32’s. These four arguments dictate the panic message, the file at which panic was invoked, and the line and column inside the file. It is up to consumers of this core library to define this panic function; it is only required to never return. This requires a
rust_eh_personality- is used by the failure mechanisms of the compiler. This is often mapped to GCC’s personality function, but crates which do not trigger a panic can be assured that this function is never called. The
langattribute is called
Strictly speaking, there are some symbols which are needed but they aren’t always necessary. ↩
!type, also called “never”.
[T; N], for the element type,
T, and the non-negative compile-time constant size,
fn(usize) -> bool.
*const T, and
[T]. Contiguous here means that elements are laid out so that every element is the same distance from its neighbors.
(T, U, ..).
()type, also called “unit”.
Clonetrait for types that cannot be ‘implicitly copied’.
Defaulttrait for types with a default value.
f32single-precision floating point type.
f64double-precision floating point type.
format_args, but can be used in some const contexts.
format_args, but adds a newline in the end.