HP gnu source-level debugger 5992-4701 manual Supported languages

For expressions you use in GDB commands, you can tell GDB to treat range errors in one of three ways: ignore them, always treat them as errors and abandon the expression, or issue warnings but evaluate the expression anyway.

A range error can result from numerical overflow, from exceeding an array index bound, or when you type a constant that is not a member of any type. Some languages, however, do not treat overflows as an error. In many implementations of C, mathematical overflow causes the result to “wrap around” to lower values―for example, if m is the largest integer value, and s is the smallest, then

m + 1 s

This, too, is specific to individual languages, and in some cases specific to individual compilers or machines. Refer to See “Supported languages” (page 105), for further details on specific languages.

GDB provides the following additional commands for controlling the range checker:

set check range auto	Set range checking on or off based on the current
	working language. See “Supported languages”
	(page 105), for the default settings for each language.
set check range on, set	Set range checking on or off, overriding the default
check range off	setting for the current working language. A warning
	is issued if the setting does not match the default
	language. If a range error occurs and range checking
	is on, then a message is printed and evaluation of the
	expression is aborted.
set check range warn	Output messages when the GDB range checker detects
	a range error, but attempt to evaluate the expression
	anyway. Evaluating the expression may still be
	impossible for other reasons, such as accessing memory
	that the process does not own (a typical example from
	many Unix systems).
show range	Show the current setting of the range checker, and
	whether or not it is being set automatically by GDB.

9.4 Supported languages

GDB supports C, C++, and Fortran. Refer to for specific information about Fortran.

Some GDB features may be used in expressions regardless of the language you use: the GDB @ and :: operators, and the '{type}addr' construct (see “Expressions” (page 83)) can be used with the constructs of any supported language.

The following section discusses GDB support for each source language. These sections are not meant to be language tutorials or references, but serve only as a reference guide to what the GDB expression parser accepts, and what input and output formats should look like for different languages.

9.4 Supported languages 105