43bec3376c
Most systems support strerror_r. For the remaining systems (e.g. MSVC) strerror_s and strerror can be used as fallbacks. We don't have a supported operating system/compiler that doesn't provide `strerror`. Close https://github.com/llvm/llvm-project/issues/62804 https://github.com/flang-compiler/f18/pull/1068 added a fallback when strerror is unavailable, but I think the code path is dead. Reviewed By: serge-sans-paille, vzakhari Differential Revision: https://reviews.llvm.org/D151718
Flang
Flang is a ground-up implementation of a Fortran front end written in modern C++. It started off as the f18 project (https://github.com/flang-compiler/f18) with an aim to replace the previous flang project (https://github.com/flang-compiler/flang) and address its various deficiencies. F18 was subsequently accepted into the LLVM project and rechristened as Flang.
Please note that flang is not ready yet for production usage.
Getting Started
Read more about flang in the docs directory. Start with the compiler overview.
To better understand Fortran as a language and the specific grammar accepted by flang, read Fortran For C Programmers and flang's specifications of the Fortran grammar and the OpenMP grammar.
Treatment of language extensions is covered in this document.
To understand the compilers handling of intrinsics, see the discussion of intrinsics.
To understand how a flang program communicates with libraries at runtime, see the discussion of runtime descriptors.
If you're interested in contributing to the compiler, read the style guide and also review how flang uses modern C++ features.
If you are interested in writing new documentation, follow LLVM's Markdown style guide.
Consult the Getting Started with Flang for information on building and running flang.