gcc/libstdc++-v3

file: libstdc++-v3/README

New users may wish to point their web browsers to the file index.html
in the 'docs' subdirectory.  It contains brief building instructions
and notes on how to configure the library in interesting ways.


Instructions for configuring and building this snapshot appear
in install.html.

This directory contains the files needed to create [a still broken
subset of] an ISO Standard C++ Library.

It has subdirectories:

  docs
     Files in HTML and text format that document usage, quirks of the
     implementation, and contributor checklists.

  include/bits
     Files included by standard headers and by other files in
     the bits directory.  Includes a set of files bits/std_xxxx.h
     that implement the standard headers <xxxx>.

  include/std
     Files meant to be found by #include <name> directives in
     standard-conforming user programs.  These headers are not
     referred to by other headers, because such dependencies
     confuse Make (leading it to delete them, all too often).
     Installations may substitute symbolic links in place of
     these files.

  include/ext
     Headers that define extensions to the standard library.  No
     standard header refers to any of them.

  include/backward
     Headers provided for backward compatibility, such as <iostream.h>.
     They are not used in this library.

  src
     Files that are used in constructing the library, but are not
     installed.

  testsuites/17_* to 27_*
     Test programs are here, and may be used to begin to exercise the 
     library.  Support for "make check" and "make check-install" is
     complete, and runs through all the subdirectories here when this
     command is issued from the build directory. Please note that
     "make check" calls the script mkcheck, which requires bash, and which
     may need the paths to bash adjusted to work properly, as /bin/bash is
     assumed.

  shadow
     Headers intended to shadow standard C headers provided by an
     underlying OS or C library, and other headers depended on directly
     by C++ headers (e.g. unistd.h).  These are meant to wrap the names
     defined there into the _C_legacy namespace.
     [NB: this can be enabled via --enable-cshadow-headers.]

  cshadow
     The contents of this directory are constructed by scripts which 
     examine the underlying C headers to discover other headers they
     depend on.  These headers are wrappers for them.
     [NB: this is still experimental, and is not currently used.]

Other subdirectories contain variant versions of certain files
that are meant to be copied or linked by the configure script.
Currently these are:

  math
  config/cpu
  config/os

Files needed only to construct the library, but not installed,
are in src/.  Files to be copied as part of an installation are
all found in the subdirectories mentioned above.  (A configure
script may link files from another directory into one of these.)

In a normal installation the bits/ directory is copied
under the std/ directory, and arranged to be searched only
when an include directive specifies a filename of "bits/..."
or <bits/...>.  When building the library, we use

  -I. -Iinclude/std -Iinclude -Iconfig/os/* -Iconfig/cpu/*

to get the same effect.

Note that glibc also has a bits/ subdirectory.  We will either
need to be careful not to collide with names in its bits/
directory; or rename bits to (e.g.) cppbits/.

To install libstdc++ you need GNU make.  The makefiles do not work with
any other make.

In files throughout the system, lines marked with an "XXX" indicate
a bug or incompletely-implemented feature.  Lines marked "XXX MT"
indicate a place that may require attention for multi-thread safety.