NAME ==== Universal::errno - Wrapper for errno modules for Unix and Windows SYNOPSIS ======== ```perl6 use Universal::errno; set_errno(2); say errno; say "failed: {errno}"; say +errno; #2 ``` DESCRIPTION =========== Universal::errno is an extension of and wrapper around lizmat's `Unix::errno`, and exports the same `errno` and `set_errno` interface. It works on Linux, Windows, and Macos. BSD support is untested, but should work. One added feature is the `strerror` method, which gets the string for the error in a thread-safe way. On platforms that support it, it uses POSIX `strerror_l`. This allows getting the error string that corresponds to the user's set locale. On platforms that don't support it, strerror_r (XSI) is used. On Windows, this is done using `GetLastError()` and `FormatMessageW`. Windows also has a `SetLastError` function which is used instead of masking the value. This module provides an Exception class, X::errno. To check the type of error in a portable way, use the `symbol` method and smartmatch against an entry in the Errno enum. It also provides a trait: error-model. Mark a sub or method with `is error-model` and the trait will automatically box the errno for you and reset errno to 0. Important note: With a native sub, the `is native` trait must come before `is error-model`. For calls that return `-errno`, there is also the trait `is error-model`. If high-performance is needed for a native sub that can return errno, use the `check-errno` and/or `check-neg-errno` subs. These subs are interchangeable with the traits, but cannot be directly applied to a nativecall subroutine. As an example of a real-world scenario, this code sets up a socket using socket(2) and handles the errors with a CATCH block. ```raku use NativeCall; use Constants::Sys::Socket; sub socket(int32, int32, int32) returns int32 is native is error-model { ... } my int32 $socket; try { $socket = socket(AF::INET, SOCK_DGRAM, 0); # Do something with $socket CATCH { when X::errno { given .symbol { when Errno::EINVAL { die "Invalid socket type" } when Errno::EACCES { die "Permission denied" } ... } } } } ``` class X::errno -------------- Exception class for errno ### method message ```perl6 method message() returns Mu ``` Get the Str message for this errno value. ### method symbol ```perl6 method symbol() returns Mu ``` Get the symbol of this errno value. ### method Int ```perl6 method Int() returns Mu ``` Get the integer that corresponds to this errno value. Subs ==== ### sub check-neg-errno ```perl6 sub check-neg-errno( Int $result ) returns Mu ``` Check the result against the negative errno form. ### sub check-errno ```perl6 sub check-errno( Int $result ) returns Mu ``` Check the result against the errno() form. AUTHOR ====== Travis Gibson CREDIT ------ Uses a heavily-modified `Unix::errno` module for Unix-like OSes, and uses `Windows::errno` (also based on lizmat's `Unix::errno`) for Windows OSes. Universal::errno::Unix contains all of the modified code, and this README also borrows the SYNOPSIS example above. The original README and COPYRIGHT information for lizmat's `Unix::errno` has been preserved in `Universal::errno::Unix`. lizmat's `Unix::errno` can be found at [https://github.com/lizmat/Unix-errno](https://github.com/lizmat/Unix-errno) COPYRIGHT AND LICENSE ===================== Copyright 2020 Travis Gibson This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.