Visible to Intel only — GUID: GUID-5C971257-3893-46E6-8BA5-0C2C003CA5E5
Visible to Intel only — GUID: GUID-5C971257-3893-46E6-8BA5-0C2C003CA5E5
Intel® Fortran Compiler Classic and Intel® Fortran Compiler Developer Guide and Reference
This document is for version 2021.9 of Intel® Fortran Compiler Classic (ifort) and version 2023.1 of Intel® Fortran Compiler (ifx).
This guide provides information about Intel® Fortran Compiler Classic (ifort) and its runtime environment, and about Intel® Fortran Compiler (ifx), which is a new compiler based on the Intel Fortran Compiler Classic (ifort) frontend and runtime libraries, using LLVM backend technology.
Refer to the Intel® Fortran Compiler product page and the Release Notes for more information about features, specifications, and downloads.
Use this guide to learn about:
- Compiler Setup: How to invoke the compiler on the command line or from within an IDE.
- Compiler Options: Information about options you can use to affect optimization, code generation, and more.
- Language Reference: Information on language syntax and semantics, on adherence to various Fortran standards, and on extensions to those standards.
- OpenMP* Support: Details about compiler support for OpenMP 5.0 Version TR4 features and some OpenMP Version 5.1 features.
- Fortran Language Extensions: Information on using additional implementation features, including creating a Component Object Model server, generating listing and map files, and more.
- Mixed-Language Programming: Information about Fortran and C interoperable procedures and data types, as well as various specifics of mixed-language programming.
- Runtime Error Messages: Information about the errors processed by the Intel® Fortran runtime library (RTL).
For more information, refer to Introducing the Intel® Fortran Compiler Classic and Intel® Fortran Compiler.
Notices and Important Information
- Support for 32-bit targets is deprecated in ifort and may be removed in a future release. ifx does not support 32-bit targets.
- macOS* support is deprecated for Intel® Fortran Compiler Classic (ifort) in the oneAPI 2023.1 release. macOS support for Intel® Fortran Compiler Classic (ifort) will not be available starting with the oneAPI 2024.0 release:
- Support for Interprocedural Optimization (IPO) is disabled for macOS SDK 11 or higher.
Xcode* integration capabilities within our Intel® Fortran Compiler bundle have been removed. The command-line interface remains fully functional for macOS.
Installing Xcode is still recommended because command-line tools from Xcode are required by the command-line compiler. However, you can install just the Xcode Command Line Tools with this command from a terminal window:
xcode-select --install
Using the Compiler Documentation
- Context Sensitive/F1 Help: To use the Context Sensitive/F1 Help feature, visit the Download Documentation: Intel® Compiler (Current and Previous) page and follow the provided instructions.
- Download Previous Versions of the Developer Guide and Reference :Visit the Download Documentation: Intel® Compiler (Current and Previous) page to download PDF or FAR HTML versions of previous compiler documentation.
For the best search experience, use a Google Chrome* or Internet Explorer* browser to view your downloaded copy of the Intel Fortran Compiler Developer Guide and Reference.
If you use Mozilla Firefox*, you may encounter an issue where the Search tab does not work. As a workaround, you can use the Contents and Index tabs or a third-party search tool to find your content.