Description of compiler options

The following sections describe the compiler options and their usage. Compiler options are listed alphabetically. All compiler options are supported by both the XL C and XL C++ compiler, unless the option title is followed by "(C only)" or "(C++ only)".

For each option, the following information is provided:
The functional category to which the option belongs is listed here.
Pragma equivalent
Many compiler options allow you to use an equivalent pragma directive to apply the option's functionality within the source code, limiting the scope of the option's application to a single source file, or even selected sections of code. Where an option supports the #pragma options (option_name) and/or #pragma name form of the directive, this is indicated.
This section provides a brief description of the effect of the option (and equivalent pragmas), and why you might want to use it.
This section provides the syntax for the option. The abbreviation of the option is used in the syntax diagram. You can also specify the option using its full name.
In most cases, the default option setting is clearly indicated in the syntax diagram. However, for many options, there are multiple default settings, depending on other compiler options in effect. This section indicates the different defaults that may apply.
This section describes the suboptions that are available for the option.
This section describes any rules or usage considerations you should be aware of when using the option. These can include restrictions on the option's applicability, valid placement of pragma directives, precedence rules for multiple option specifications, and so on.
IPA effects
Where appropriate, provides information on the effect of the option during the IPA compile and/or IPA link steps.
Predefined macros
Many compiler options set macros that are protected (that is, cannot be undefined or redefined by the user). Where applicable, any macros that are predefined by the option, and the values to which they are defined, are listed in this section.
Where appropriate, examples of the command-line syntax are provided in this section.
Related information
Where appropriate, provides cross-references to related information.