The GNU C++ Iostream Library - 1. Introduction

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Copyright (C) 1993 Free Software Foundation, Inc.

`libio` includes software developed by the University of California, Berkeley.

`libio` uses floating-point software written by David M. Gay, which includes the following notice:

> The author of this software is David M. Gay.

> Copyright (c) 1991 by AT&T.

> Permission to use, copy, modify, and distribute this software for any purpose without fee is hereby granted, provided that this entire notice is included in all copies of any software which is or includes a copy or modification of this software and in all copies of the supporting documentation for such software.

> THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED WARRANTY. IN PARTICULAR, NEITHER THE AUTHOR NOR AT&T MAKES ANY REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.

Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.

Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided also that the entire resulting derived work is distributed under the terms of a permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions.

# 1. Introduction

The iostream classes implement most of the features of AT&T version 2.0 iostream library classes, and most of the features of the ANSI X3J16 library draft (which is based on the AT&T design).

This manual is meant as a reference; for tutorial material on iostreams, see the corresponding section of any recent popular introduction to C++.

## 1.1 Licensing terms for `libio`

Since the `iostream` classes are so fundamental to standard C++, the Free Software Foundation has agreed to a special exception to its standard license, when you link programs with `libio.a`:

> As a special exception, if you link this library with files compiled with a GNU compiler to produce an executable, this does not cause the resulting executable to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the executable file might be covered by the GNU General Public License.

The code is under the GNU General Public License (version 2) for all other purposes than linking with this library; that means that you can modify and redistribute the code as usual, but remember that if you do, your modifications, and anything you link with the modified code, must be available to others on the same terms.

These functions are also available as part of the `libg++` library; if you link with that library instead of `libio`, the GNU Library General Public License applies.

## 1.2 Acknowledgements

Per Bothner wrote most of the `iostream` library, but some portions have their origins elsewhere in the free software community. Heinz Seidl wrote the IO manipulators. The floating-point conversion software is by David M. Gay of AT&T. Some code was derived from parts of BSD 4.4, which was written at the University of California, Berkeley.

The iostream classes are found in the `libio` library. An early version was originally distributed in `libg++`, and they are still included there as well, for convenience if you need other `libg++` classes. Doug Lea was the original author of `libg++`, and some of the file-management code still in `libio` is his.

Various people found bugs or offered suggestions. Hongjiu Lu worked hard to use the library as the default stdio implementation for Linux, and has provided much stress-testing of the library.

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