cvt-trait 0.1.15

Reimplementation of the private std::sys::cvt(), but as a trait method.

Example

use cvt_trait::prelude::*;
# use std::os::raw::c_int;
# #[cfg(unix)]
# unsafe fn os_api() -> c_int {
#     0
# }
# #[cfg(windows)]
# unsafe fn os_api() -> c_int {
#    1
# }
unsafe { os_api() }.cvt().expect("OS API failed");