Intel® C++ Compiler Classic Developer Guide and Reference

ID 767249
Date 7/13/2023
Public
Document Table of Contents

Pragmas

Pragmas are directives that provide instructions to the compiler for use in specific cases. For example, you can use the novector pragma to specify that a loop should never be vectorized. The keyword #pragma is standard in the C++ language, but individual pragmas are machine-specific or operating system-specific, and vary by compiler.

Some pragmas provide the same functionality as compiler options. Pragmas override behavior specified by compiler options.

Some pragmas are available for both Intel® and non-Intel microprocessors but they may perform additional optimizations for Intel® microprocessors than they perform for non-Intel microprocessors. Refer to the individual pragma name for detailed description.

The Intel® C++ Compiler Classic pragmas are categorized as follows:

  • Intel-specific Pragmas - pragmas developed or modified by Intel to work specifically with the Intel® C++ Compiler Classic

  • Intel Supported Pragmas - pragmas developed by external sources that are supported by the Intel® C++ Compiler Classic for compatibility reasons

Using Pragmas

You enter pragmas into your C++ source code using the following syntax:

#pragma <pragma name>

Individual Pragma Descriptions

Each pragma description has the following details:

Section

Description

Short Description

Contains a brief description of what the pragma does.

Syntax

Contains the pragma syntax.

Arguments

Contains a list of the arguments (parameters).

Description

Contains a detailed description of what the pragma does.

Example

Contains typical usage example/s.

See Also

Contains links or paths to other pragmas or related topics.