Macros

Macros
Prev	Chapter 3. Using	Next

+ All library macros begin with _GLIBCXX_. +

+ Furthermore, all pre-processor macros, switches, and + configuration options are gathered in the + file c++config.h, which + is generated during the libstdc++ configuration and build + process. This file is then included when needed by files part of + the public libstdc++ API, like <ios>. Most of these macros + should not be used by consumers of libstdc++, and are reserved + for internal implementation use. These macros cannot + be redefined. +

+ A select handful of macros control libstdc++ extensions and extra + features, or provide versioning information for the API. Only + those macros listed below are offered for consideration by the + general public. +

Below is the macro which users may check for library version + information.

__GLIBCXX__: The current version of + libstdc++ in compressed ISO date format, form of an unsigned + long. For details on the value of this particular macro for a + particular release, please consult this + document. +

Below are the macros which users may change with #define/#undef or + with -D/-U compiler flags. The default state of the symbol is + listed.

“Configurable” (or “Not configurable”) means + that the symbol is initially chosen (or not) based on + --enable/--disable options at library build and configure time + (documented here), with the + various --enable/--disable choices being translated to + #define/#undef). +

ABI means that changing from the default value may + mean changing the ABI of compiled code. In other words, these + choices control code which has already been compiled (i.e., in a + binary such as libstdc++.a/.so). If you explicitly #define or + #undef these macros, the headers may see different code + paths, but the libraries which you link against will not. + Experimenting with different values with the expectation of + consistent linkage requires changing the config headers before + building/installing the library. +

_GLIBCXX_USE_DEPRECATED: + Defined by default. Not configurable. ABI-changing. Turning this off + removes older ARM-style iostreams code, and other anachronisms + from the API. This macro is dependent on the version of the + standard being tracked, and as a result may give different results for + -std=c++98 and -std=c++0x. This may + be useful in updating old C++ code which no longer meet the + requirements of the language, or for checking current code + against new language standards. +
_GLIBCXX_FORCE_NEW: + Undefined by default. When defined, memory allocation and + allocators controlled by libstdc++ call operator new/delete + without caching and pooling. Configurable via + --enable-libstdcxx-allocator. ABI-changing. +
_GLIBCXX_CONCEPT_CHECKS: + Undefined by default. Configurable via + --enable-concept-checks. When defined, performs + compile-time checking on certain template instantiations to + detect violations of the requirements of the standard. This + is described in more detail here. +
_GLIBCXX_DEBUG: + Undefined by default. When defined, compiles user code using + the debug mode. +
_GLIBCXX_DEBUG_PEDANTIC: + Undefined by default. When defined while compiling with + the debug mode, makes + the debug mode extremely picky by making the use of libstdc++ + extensions and libstdc++-specific behavior into errors. +
_GLIBCXX_PARALLEL: Undefined by default. When defined, compiles user code + using the parallel + mode. +
_GLIBCXX_PROFILE: Undefined by default. When defined, compiles user code + using the profile + mode. +

Prev	Up	Next
Headers	Home	Namespaces