//! Utilities to read errors.
//!
//! Only one error can be registered at a time. Error are registered
//! by Rust only, and are usually read by C or C++.
//!
//! Reading an error from C or C++ happens in 2 steps: Getting the
//! error's length with [`wasmer_last_error_length`], and then reading
//! the actual error with [`wasmer_last_error_message`].
//!
//! # Example
//!
//! ```rust
//! # use wasmer_inline_c::assert_c;
//! # fn main() {
//! # (assert_c! {
//! # #include "tests/wasmer.h"
//! #
//! int main() {
//! // Create an invalid WebAssembly module from a WAT definition,
//! // it will generate an error!
//! wasm_byte_vec_t wat;
//! wasmer_byte_vec_new_from_string(&wat, "(foobar)");
//! wasm_byte_vec_t wasm;
//! wat2wasm(&wat, &wasm);
//!
//! int error_length = wasmer_last_error_length();
//!
//! // There is an error!
//! assert(error_length > 0);
//!
//! char *error_message = malloc(error_length);
//! wasmer_last_error_message(error_message, error_length);
//! printf("Error message: %s\n", error_message);
//!
//! // Side note: The error has now been cleared on the Rust side!
//! assert(wasmer_last_error_length() == 0);
//!
//! // Free everything.
//! free(error_message);
//! wasm_byte_vec_delete(&wasm);
//! wasm_byte_vec_delete(&wat);
//!
//! return 0;
//! }
//! # })
//! # .success();
//! # }
//! ```
use ;
use RefCell;
use Display;
use ;
use slice;
thread_local!
/// Rust function to register a new error.
///
/// # Example
///
/// ```rust,no_run
/// # use wasmer::error::update_last_error;
///
/// update_last_error("Hello, World!");
/// ```
/// Retrieve the most recent error, clearing it in the process.
pub
/// Gets the length in bytes of the last error if any, zero otherwise. This
/// includes th NUL terminator byte.
///
/// This can be used to dynamically allocate a buffer with the correct number of
/// bytes needed to store a message.
///
/// # Example
///
/// See this module's documentation to get a complete example.
// TODO(Amanieu): This should use size_t
pub extern "C"
/// Gets the last error message if any into the provided buffer
/// `buffer` up to the given `length`.
///
/// The `length` parameter must be large enough to store the last
/// error message. Ideally, the value should come from
/// [`wasmer_last_error_length`].
///
/// The function returns the length of the string in bytes, `-1` if an
/// error occurs. Potential errors are:
///
/// * The `buffer` is a null pointer,
/// * The `buffer` is too small to hold the error message.
///
/// Note: The error message always has a trailing NUL character.
///
/// Important note: If the provided `buffer` is non-null, once this
/// function has been called, regardless whether it fails or succeeds,
/// the error is cleared.
///
/// # Example
///
/// See this module's documentation to get a complete example.
// TODO(Amanieu): This should use size_t
pub unsafe extern "C"