Struct c2rust_refactor::transform::format::ConvertFormatArgs

pub struct ConvertFormatArgs;

convert_format_args Command

Usage: convert_format_args

Marks: target

For each function call, if one of its argument expressions is marked target, then parse that argument as a printf format string, with the subsequent arguments as the format args. Replace both the format string and the args with an invocation of the Rust format_args! macro.

This transformation applies casts to the remaining arguments to account for differences in argument conversion behavior between C-style and Rust-style string formatting. However, it does not attempt to convert the format_args! output into something compatible with the original C function. This results in a type error, so this pass should usually be followed up by an additional rewrite to change the function being called.

Example:

printf("hello %d\n", 123);

If the string "hello %d\n" is marked target, then running convert_format_string will replace this call with

printf(format_args!("hello {:}\n", 123 as i32));

At this point, it would be wise to replace the printf expression with a function that accepts the std::fmt::Arguments produced by format_args!.

Trait Implementations

impl Transform for ConvertFormatArgs

fn transform(&self, krate: &mut Crate, st: &CommandState, _cx: &RefactorCtxt)

Apply the transformation.

fn min_phase(&self) -> Phase

Return the minimum phase at which this transform can operate. See the Phase docs for details. The default is Phase2.