Table of Contents
+ By default, libstdc++ is built with efficiency in mind, and + therefore performs little or no error checking that is not + required by the C++ standard. This means that programs that + incorrectly use the C++ standard library will exhibit behavior + that is not portable and may not even be predictable, because they + tread into implementation-specific or undefined behavior. To + detect some of these errors before they can become problematic, + libstdc++ offers a debug mode that provides additional checking of + library facilities, and will report errors in the use of libstdc++ + as soon as they can be detected by emitting a description of the + problem to standard error and aborting the program. This debug + mode is available with GCC 3.4.0 and later versions. +
+ The libstdc++ debug mode performs checking for many areas of the + C++ standard, but the focus is on checking interactions among + standard iterators, containers, and algorithms, including: +
Safe iterators: Iterators keep track of the + container whose elements they reference, so errors such as + incrementing a past-the-end iterator or dereferencing an iterator + that points to a container that has been destructed are diagnosed + immediately.
Algorithm preconditions: Algorithms attempt to
+ validate their input parameters to detect errors as early as
+ possible. For instance, the set_intersection
+ algorithm requires that its iterator
+ parameters first1 and last1 form a valid
+ iterator range, and that the sequence
+ [first1, last1) is sorted according to
+ the same predicate that was passed
+ to set_intersection; the libstdc++ debug mode will
+ detect an error if the sequence is not sorted or was sorted by a
+ different predicate.