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@settitle GNU @code{autosprintf}
@finalout
@c Indices:
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@c %**end of header
@set VERSION 1.0

@ifinfo
@dircategory C++ libraries
@direntry
* autosprintf: (autosprintf).   Support for printf format strings in C++.
@end direntry
@end ifinfo

@ifinfo
This file provides documentation for GNU @code{autosprintf} library.

@copying
Copyright (C) 2002-2003, 2006-2007 Free Software Foundation, Inc.

This manual is free documentation.  It is dually licensed under the
GNU FDL and the GNU GPL.  This means that you can redistribute this
manual under either of these two licenses, at your choice.

This manual is covered by the GNU FDL.  Permission is granted to copy,
distribute and/or modify this document under the terms of the
GNU Free Documentation License (FDL), either version 1.2 of the
License, or (at your option) any later version published by the
Free Software Foundation (FSF); with no Invariant Sections, with no
Front-Cover Text, and with no Back-Cover Texts.
A copy of the license is at @url{http://www.gnu.org/licenses/fdl.html}.

This manual is covered by the GNU GPL.  You can redistribute it and/or
modify it under the terms of the GNU General Public License (GPL), either
version 2 of the License, or (at your option) any later version published
by the Free Software Foundation (FSF).
A copy of the license is at @url{http://www.gnu.org/licenses/gpl.html}.
@end copying
@end ifinfo

@titlepage
@title GNU autosprintf, version @value{VERSION}
@subtitle Formatted Output to Strings in C++
@author Bruno Haible

@page
@vskip 0pt plus 1filll
@c @insertcopying
Copyright (C) 2002-2003, 2006-2007 Free Software Foundation, Inc.

This manual is free documentation.  It is dually licensed under the
GNU FDL and the GNU GPL.  This means that you can redistribute this
manual under either of these two licenses, at your choice.

This manual is covered by the GNU FDL.  Permission is granted to copy,
distribute and/or modify this document under the terms of the
GNU Free Documentation License (FDL), either version 1.2 of the
License, or (at your option) any later version published by the
Free Software Foundation (FSF); with no Invariant Sections, with no
Front-Cover Text, and with no Back-Cover Texts.
A copy of the license is at @url{http://www.gnu.org/licenses/fdl.html}.

This manual is covered by the GNU GPL.  You can redistribute it and/or
modify it under the terms of the GNU General Public License (GPL), either
version 2 of the License, or (at your option) any later version published
by the Free Software Foundation (FSF).
A copy of the license is at @url{http://www.gnu.org/licenses/gpl.html}.
@end titlepage

@ifset makeinfo
@node Top, Introduction, (dir), (dir)
@top GNU autosprintf

This manual documents the GNU autosprintf class, version @value{VERSION}.

@menu
* Introduction::                Introduction
* Class autosprintf::           The @code{autosprintf} class
* Using autosprintf::           Using @code{autosprintf} in own programs
@end menu

@end ifset

@node Introduction, Class autosprintf, Top, Top
@chapter Introduction

This package makes the C formatted output routines (@code{fprintf} et al.)
usable in C++ programs, for use with the @code{<string>} strings and the
@code{<iostream>} streams.

It allows to write code like

@smallexample
cerr << autosprintf ("syntax error in %s:%d: %s", filename, line, errstring);
@end smallexample

@noindent
instead of

@smallexample
cerr << "syntax error in " << filename << ":" << line << ": " << errstring;
@end smallexample

The benefits of the autosprintf syntax are:

@itemize @bullet
@item
It reuses the standard POSIX printf facility. Easy migration from C to C++.

@item
English sentences are kept together.

@item
It makes internationalization possible. Internationalization requires format
strings, because in some cases the translator needs to change the order of a
sentence, and more generally it is easier for the translator to work with a
single string for a sentence than with multiple string pieces.

@item
It reduces the risk of programming errors due to forgotten state in the
output stream (e.g.@: @code{cout << hex;} not followed by @code{cout << dec;}).
@end itemize

@node Class autosprintf, Using autosprintf, Introduction, Top
@chapter The @code{autosprintf} class

An instance of class @code{autosprintf} just contains a string with the
formatted output result. Such an instance is usually allocated as an
automatic storage variable, i.e.@: on the stack, not with @code{new} on the
heap.

The constructor @code{autosprintf (const char *format, ...)} takes a format
string and additional arguments, like the C function @code{printf}.

Conversions to @code{char *} and @code{std::string} are defined that return
the encapsulated string.  The conversion to @code{char *} returns a freshly
allocated copy of the encapsulated string; it needs to be freed using
@code{delete[]}.  The conversion to @code{std::string} returns a copy of
the encapsulated string, with automatic memory management.

The destructor @code{~autosprintf ()} destroys the encapsulated string.

An @code{operator <<} is provided that outputs the encapsulated string to the
given @code{ostream}.

@node Using autosprintf,  , Class autosprintf, Top
@chapter Using @code{autosprintf} in own programs

To use the @code{autosprintf} class in your programs, you need to add

@smallexample
#include "autosprintf.h"
using gnu::autosprintf;
@end smallexample

@noindent
to your source code.
The include file defines the class @code{autosprintf}, in a namespace called
@code{gnu}. The @samp{using} statement makes it possible to use the class
without the (otherwise natural) @code{gnu::} prefix.

When linking your program, you need to link with @code{libasprintf}, because
that's where the class is defined. In projects using GNU @code{autoconf},
this means adding @samp{AC_LIB_LINKFLAGS([asprintf])} to @code{configure.in}
or @code{configure.ac}, and using the @@LIBASPRINTF@@ Makefile variable that
it provides.

@bye

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