printf-wrap is a Rust crate with types to help developers write safe wrappers for
C functions using [printf(3)]-style format strings and varargs.
In particular, PrintfFmt<(T_1, T_2, ..., T_N)> is a wrapper around a null-terminated string
that is guaranteed to be a valid format string for use with N arguments of types
T_1, T_2, …, T_N
when the arguments are mapped through the PrintfArgument::as_c_val() method.
The following example shows a safe wrapper for calling printf with two arguments,
along with a use of it.
```rust use printfwrap::{PrintfFmt, PrintfArgument}; use libc::{cint, printf};
/// Safe wrapper for calling printf with two value arguments.
pub fn printfwith2args
const MYFORMATSTRING: PrintfFmt<(u32, i32)> = PrintfFmt::neworpanic("unsigned = %u, signed = %d\0");
fn main() { printfwith2args(MYFORMAT_STRING, 42, -7); } ```
In the example, MY_FORMAT_STRING is determined to be a valid format string
for arguments of (u32, i32) at compile time, with zero runtime overhead.
With a little macro magic, generating wrappers for different numbers of post-format
arguments is easy, with printf-wrap handling the validation and conversion of
values to C-compatible equivalents.
std – enables support for the [CStr] and [CString] types from [std].
Enabled by default; if you want to use this crate in #[no_std] environments,
[default-features = false] in the dependency declaration is your friend.
example – enables a demonstration of the use of printf-wrap
with some wrappers around functions from the C standard library.
This crate is licensed under either of the MIT license or the Apache License version 2.0 at your option.