Intel® Fortran Compiler Classic and Intel® Fortran Compiler Developer Guide and Reference

This document is for version 2021.6 of Intel® Fortran Compiler Classic (ifort) and version 2022.1 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 main page 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.
Run-Time 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* is supported for the ifort compiler. However, 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.

Keep in mind that installation of 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.

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