Using MySQL++ in Your Own ProjectUp to now, this manual has only discussed MySQL++
in conjunction with the example programs that come with the
library. This chapter covers the steps you need to take to
incorporate MySQL++ into your own projects.The first thing you have to do is include
mysql++.h in each module
that uses MySQL++. In modules that use SSQLS v1, you also need to include
ssqls.h.MySQL++ has many header
files, but the only one that isn’t intertwined with the rest is
ssqls.h. mysql++.h brings
in all of the others in the correct order. Some have tried to speed
their build times by finding a subset of MySQL++ headers to include,
but mysql++.h already does as much of this as
is practical. MySQL++’s monolithic nature rules out finding
a true subset of the library headers.At this point, your project probably still won’t compile,
and it certainly won’t link. The remaining steps are dependent
on the operating system and tools you are using. The rest of this
chapter is broken up into several sections, one for each major
platform type. You can skip over the sections for platforms you
don’t use.Visual C++Using MySQL++ in an MFC ProjectIf you don’t already have a project set up, open
Visual Studio, say File | New | Project, then choose Visual C++
| MFC | MFC Application. Go through the wizard setting up the
project as you see fit.Once you have your project open, right click on your
top-level executable in the Solution Explorer, choose Properties,
and make the following changes. (Where it doesn’t
specify Debug or Release, make the same change to both
configurations.)Append the following to C/C++
| General | Additional Include Directories:
C:\Program Files\MySQL\MySQL Server 5.0\include,
C:\mysql++\includeUnder C/C++ | Code Generation change
“Runtime Library” to “Multi-threaded
Debug DLL (/MDd)” for the Debug configuration. For
the Release configuration, make it “Multi-threaded DLL
(/MD)”.Append the following to Linker | General |
Additional Library Directories for the Debug configuration:
C:\Program Files\MySQL\MySQL Server 5.0\lib\debug,
C:\mysql++\vc\debugFor the Release configuration, make it the same,
but change the “debug” directory names to
“opt”.Under Linker | Input add the following to
“Additional Dependencies” for the Debug
configuration: libmysql.lib wsock32.lib
mysqlpp_d.lib...and then for the Release configuration:
libmysql.lib wsock32.lib
mysqlpp.libThis difference is because MySQL++’s Debug
DLL and import library have a _d
suffix so you can have both in the same directory without
conflicts.You may want to study
examples\vstudio\mfc\mfc.vcproj
to see this in action. Note that some of the paths will
be different, because it can use relative paths for
mysqlpp.dll.Using MySQL++ in a Windows Forms C++/CLI ProjectBefore you start work on getting MySQL++ working with your
own program, you need to make some changes to the MySQL++ build
settings. Open mysqlpp.sln, then right-click
on the mysqlpp target and select Properties. Make the following
changes for both the Debug and Release configurations:Under Configuration Properties | General,
change “Common Language Runtime support” to the
/clr setting.Under C/C++ | Code Generation, change
“Enable C++ Exceptions” from “Yes
(/EHsc)” to “Yes With SEH Exceptions
(/EHa)”If you have already built MySQL++, be sure to perform a
complete rebuild after changing these options. The compiler
will emit several C4835 warnings after making those changes,
which are harmless when using the DLL with a C++/CLI
program, but which warn of real problems when using it with
unmanaged C++. This is why MySQL++’s Windows installer
(install.hta) offers the option to install
the CLR version into a separate directory; use it if you need
both managed and unmanaged versions installed!For the same reason, you might give some thought about
where you install mysqlpp.dll on your
end user’s machines when distributing your program.
My recommendation is to install it in the same directory as
the .exe file that uses it, rather than
installing into a system directory where it could conflict
with a mysqlpp.dll built with different
settings.Once you have MySQL++ built with CLR support, open your
program’s project. If you don’t already have a
project set up, open Visual Studio, say File | New | Project,
then choose Visual C++ | CLR | Windows Forms Application.
Go through the wizard setting up the project as you see
fit.The configuration process isn’t much different from
that for an MFC project, so go through the list above first.
Then, make the following changes particular to .NET and
C++/CLI:Under Configuration Properties | General
change the setting from /clr:pure to /clr. (You need mixed
assembly support to allow a C++/CLI program to use a plain C++
library like MySQL++.)For the Linker | Input settings, you
don’t need wsock32.lib. The mere
fact that you’re using .NET takes care of that dependency
for you.In the MFC instructions above, it said that you need to
build it using the Multi-threaded DLL version of the C++ Runtime
Library. That’s not strictly true for MFC, but it’s
an absolute requirement for C++/CLI. See the Remarks in the
MSDN article on the /clr switch for details.You may want to study
examples\vstudio\wforms\wforms.vcproj
to see all this in action. Note that some of the
paths will be different, because it can use relative
paths for mysqlpp_d.dll and
mysqlpp.dll.Unixy Platforms: Linux, *BSD, OS X, Cygwin, Solaris...There are lots of ways to build programs on Unixy
platforms. We’ll cover just the most generic way
here, Makefiles. We’ll use a very
simple example so it’s clear how to translate this to
more sophisticated build systems such as GNU Autotools or
Bakefile.“Hello, world!” for MySQL++ might look something
like this:Here’s a Makefile for building
that program:The first three lines are where all of the assumptions
about file and path names are laid out. Probably at least one of
these assumptions isn’t true for your system, and so will
require changing.The trickiest line is the third one. MySQL++ programs
need to get built against both the MySQL and MySQL++
libraries, because MySQL++ is built on top of the MySQL C
API library. If you’re building a threaded program,
use -lmysqlclient_r instead. (See for more details on building thread-aware
programs.)On some systems, the order of libraries in the
LDFLAGS line is important: these linkers collect
symbols from right to left, so the rightmost library needs to
be the most generic. In this example, MySQL++ depends on MySQL,
so the MySQL C API library is rightmost.You might need to add more libraries to the
LDFLAGS line. -lnsl,
-lz and -lm are
common. If you study how MySQL++ itself gets built on your system,
you can see what it uses, and emulate that.Beyond that, we have a pretty vanilla
Makefile. We don’t have any special
dependency or build rules, because the default rules should work
fine, particularly if you’re using GNU make, which is just
about universal these days.OS XMakefilesThe generic Makefile
instructions above cover most of what you need to know
about using Makefiles on OS X.One thing that may trip you up on OS X is that it uses an
uncommon dynamic linkage system. The easiest way to cope with
this is to link your executables with the compiler, rather than
call ld directly.Another tricky bit on OS X is the concept of Universal
binaries. See README-Mac-OS-X.txt for
details on building a Universal version of the MySQL++ library,
if you need one. By default, you only get a version tuned for
the system type you build it on.XcodeI have no information on how to incorporate MySQL++ in
an Xcode project. Send a message to the MySQL++ mailing list
if you can help out here.MinGWMakefilesThe generic Makefile instructions
above apply to MinGW’s version of GNU make as
well. You will have some differences due to the platform, so
here’s the adjusted Makefile:Note the use of forward slashes. GNU make uses the
backslash as an escape character, so you’d have to double
them if you’re unwilling to use forward slashes.Also note that I’ve used del
instead of rm in the clean target. Unless
there is a program called sh.exe in
your PATH, MinGW make uses Windows’
cmd.exe for shell commands. The most likely
reason to have sh.exe is if you also have
Cygwin or MSYS installed. The next section covers the best way
I’ve found to cope with that.Working with MinGW Under CygwinCompared to Unix, the biggest difference you’ll
find is that MinGW calls its make
executable mingw32-make. As I understand
it, this is to allow it to coexist with Cygwin, since the two
versions have some behavioral differences, despite both being
based on GNU Make. A Makefile written
for one is likely to fail to work correctly with the other,
so you have to be able to specify which one you mean.If you have both MinGW and Cygwin installed, you may be
tempted to use Cygwin’s superior command line environment
over a Windows command shell or MSYS. If you’re like me,
you type make reflexively now; typing
mingw32-make instead isn’t going
to work. Another problem with having Cygwin and MinGW on the
same system is that this puts a sh.exe
program in your system’s PATH
which makes MinGW make send shell commands to it instead of
cmd.exe as it normally would. I find it
best to set up a special MinGW environment to avoid problems
stemming from these platform differences.I’ve created a pair of scripts that let me work
in Cygwin mode most of the time and temporarily drop down
into “MinGW mode” only when necessary. I call the
first script mingw, and put it somewhere
in the Cygwin PATH:
#!/bin/sh
PATH=/cygdrive/c/mingw/bin:/cygdrive/c/windows:/cygdrive/c/windows/system32:/cygdrive/c/cygwin/bin
echo "Say 'exit' to leave MinGW shell and restore Cygwin environment."
/usr/bin/bash --rcfile ~/.mingwrcThen there’s a tiny little file called
.mingwrc that goes in your Cygwin home
directory:
alias make=mingw32-make
PS1='MinGW: \W \$ '(This split is necessary due to the way Bash works.)The first script sets up most of the MinGW environment,
putting the MinGW and Windows directories ahead of the Cygwin
directory so programs in those locations take precedence. Then
the second script finishes setting up the MinGW sub-shell,
causing the make command to invoke
MinGW’s make program instead of Cygwin’s, and
changing the command prompt to remind you that you’re
in a sub-shell. Just say exit to get back
to Cygwin mode.Third-Party MinGW IDEs (Dev-C++, Code::Blocks...)I have no information on how to do this. We’ve
received reports on the mailing list from people that have made
it work, but no specifics on what all needs to be done. The
Makefile discussion above should give you some hints.EclipseAs far as I can tell, the simplest way to build a C++
project with Eclipse is to set up a Makefile for it as described
above, then add an external
run configuration for your local make tool. Get the project
building from the command line with make, then go to Run |
External Tools | Open External Tools Dialog and add a new launch
configuration.For example, on my OS X system I use
/usr/bin/gnumake for the program location
and pick the project root with the Browse Workspace button to
set the working directory.