# Intel® C++ Compiler Classic Developer Guide and Reference

This is for version 2021.4 of the compiler.

This document contains information about the Intel® C++ Compiler Classic (icc for Linux* and icl for Windows*) compiler and runtime environment. The Intel® C++ Compiler Classic can be found in the Intel® oneAPI HPC Toolkit, Intel® oneAPI IoT Toolkit, or as a standalone compiler. More information and specifications can be found on the Intel® oneAPI DPC++/C++ Compiler main page.

The following are some important sections of the compiler developer guide:

Compiler Setup | Compiler Setup explains how to invoke the compiler on the command line or from within an IDE.
OpenMP* Support | The compiler supports many OpenMP* features, including most of OpenMP* Version TR4: Version 5.0.
Compiler Options | Compiler Options provides information about options you can use to affect optimization, code generation, and more.
Intrinsics | Intrinsics let you generate more readable code, simplify instruction scheduling, reduce debugging, access the instructions that cannot be generated using the standard constructs of the C and C++ languages, and more.
Pragmas | Pragmas provide the compiler with the instructions for specific tasks, such as splitting large loops into smaller ones, enabling or disabling optimization for code, or offloading computation to the target.
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 instructions provided there.
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. ### Note 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.