vmime/doc/book/start.tex
2018-09-05 23:54:48 +02:00

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\chapter{Getting Started}
% ============================================================================
\section{Using VMime in your programs}
First, make sure you have successfully compiled and installed VMime using the
instructions described in Chapter \ref{chapter_building}. To use VMime in your
program, you simply have to include VMime headers:
\begin{lstlisting}
#include <vmime/vmime.hpp>
\end{lstlisting}
\vnote{for versions older than 0.6.1, include $<$vmime/vmime$>$.}
As of version 0.6.1, VMime uses {\vcode pkg-config} to simplify compiling and
linking with VMime. The {\vcode pkg-config} utility is used to detect the
appropriate compiler and linker flags needed for a library.
You can simply build your program with:
\begin{verbatim}
$ g++ `pkg-config --cflags --libs vmime` -static -o myprog myprog.cpp
\end{verbatim}
to use the static version, or with:
\begin{verbatim}
$ g++ `pkg-config --cflags vmime` -o myprog myprog.cpp `pkg-config --libs vmime`
\end{verbatim}
to use the shared version.
\vnote{it is highly recommended that you link your program against the shared
version of the library.}
All VMime classes and global functions are defined in the namespace
{\vcode vmime}, so prefix explicitely all your declarations which use VMime
with {\vcode vmime::}, or import the {\vcode vmime} namespace into the global
namespace with the C++ keywork {\vcode using} (not recommended, though).
% ============================================================================
\section{If you can not (or do not want to) use {\vcode pkg-config}}
{\bf Linking with the shared library (.so):} compile your program with the
{\vcode -lvmime} flag. You can use the -L path flag if the library file is
not in a standard path (ie. not in /usr/lib or /usr/local/lib).
\vnote{if you want to link your program with the shared version of VMime
library, make sure the library has been compiled using CMake build system
({\vcode make}, then {\vcode make install}). When you compile with SCons,
only the static library is built and installed.}
{\bf Linking with the static library (.a):} follow the same procedure as for
shared linking and append the flag -static to force static linking. Although
static linking is possible, you are encouraged to use the shared (dynamic)
version of the library.
% ============================================================================
\section{Platform-dependent code}
While the most part of VMime code is pure ANSI C++, there are some features
that are platform-specific: file management (opening/reading/writing files),
network code (socket, DNS resolution) and time management. All the
non-portable stuff is done by a bridge object called a platform handler (see
{\vcode vmime::platform}).
If your platform is POSIX-compatible (eg. GNU/Linux, *BSD) or is Windows,
then you are lucky: VMime has built-in support for these platforms. If not,
don't worry, the sources of the built-in platform handlers are very well
documented, so writing you own should not be very difficult.
If your VMime version is $<=$ 0.9.1, you should tell VMime which platform
handler you want to use at the beginning of your program (before using
\emph{any} VMime object, or calling \emph{any} VMime global function).
So, if your platform is POSIX, your program should look like this:
\begin{lstlisting}[caption={Initializing VMime and the platform handler}]
#include <vmime/vmime.hpp>
#include <vmime/platforms/posix/posixHandler.hpp>
int main() {
vmime::platform::
setHandler <vmime::platforms::posix::posixHandler>();
// Now, you can use VMime
// ...do what you want, it's your program...
}
\end{lstlisting}
For using VMime on Windows, include
{\vcode vmime/platforms/windows/windowsHandler.hpp} and use the following line
to initialize the platform handler:
\begin{lstlisting}
vmime::platform::
setHandler <vmime::platforms::windows::windowsHandler>();
\end{lstlisting}
\vnote{since version 0.9.2, this is not needed any more: the platform
handler is installed automatically using the platform detected during the
build configuration.}
\vnote{since version 0.8.1, {\vcode vmime::platformDependant} was renamed
to {\vcode vmime::platform}. The old name has been kept for compatibility
but it is recommended that you update your code, if needed.}