Macro cstr 

macro_rules! cstr {
    ($s:expr) => { ... };
    () => { ... };
}

Available on non-crate feature lock only.

Convert String to *mut i8.

Kept for use with the unsafe C API. The string is leaked: it has to outlive the C call, and there is no way for the macro to know when that is. Prefer ffi::to_cstring, which hands back an owned std::ffi::CString.

Panics

Panics if the string contains an interior null byte.