How to make a Makefile?

Most software compiled on BLU (BSD/Linux/Unix) operating systems is done using make.

The simplest Makefile

The simplest Makefile compiles one single executable. Think of your simplest “Hello, World!” project.

HelloWorld.cpp

#include <iostream>
using namespace std;
int main() {
  cout << "Hello, World!";
  return(0);
}

Of course, for one file you don’t need a Makefile. You could simply run this command that will compile hw.cpp

g++ -o HelloWorld HelloWorld.cpp

So even though a Makefile seems useless for a single file, here is how you would do it.

all:
	g++ -o HelloWorld HelloWorld.cpp

Notice that you have a label and the same compile command one line below the label.

Important! The syntax requires the second line to start with a tab.

Adding objects to your Makefile

Lets assume instead of one file, you have the three file HelloWord.

  • Main.cpp
  • HelloWorld.h
  • HelloWord.cpp

Main.cpp

#include <iostream>
#include "HelloWorld.h"

using namespace std;

int main()
{
  HelloWorld hw = HelloWorld();
  cout << hw.Text << endl;
}

HelloWorld.h

#include <iostream>

using namespace std;

class HelloWorld
{
public:
  HelloWorld();
  ~HelloWorld();

  string Text;
};

HelloWorld.cpp

#include "HelloWorld.h"

HelloWorld::HelloWorld()
{
  Text = string("Hello, World!");
}

HelloWorld::~HelloWorld()
{
}

This simple project can also easily be compiled without a Makefile using this command line.

g++ -o HelloWorld Main.cpp HelloWorld.cpp

However, even with only three files you can start to see how it is much easier to type make than the lengthening command above.

Makefile

all:
	g++ -o HelloWorld Main.cpp HelloWorld.cpp

This is not perfect however, as this compiles both files every time make is run. If changes are made only to Main.cpp there is no reason to recompile HelloWorld.cpp. We can accomplish this by compiling HelloWorld.cpp to a HelloWorld.o module.

all: HelloWorld.o
	g++ -o HelloWorld Main.cpp HelloWorld.o

Similarly if you make changes to HelloWorld.h or HelloWorld.cpp, why do you need to recompile Main.cpp? So you can make it a module too.

all: Main.o HelloWorld.o
	g++ -o HelloWorld Main.o HelloWorld.o

Now only the libraries that have been modified will be recompiled when you run make. This can save significant build time when the project size increases.

Using variables in your Makefile

Mistakes are annoying.  Having to type the same thing in multiple places often leads to mistakes and typos. If you look at the above, there is duplication that is unnecessary.

Makefile with duplication

all: Main.o HelloWorld.o
	g++ -o HelloWorld Main.o HelloWorld.o

Makefile using a variable to avoid duplication

objs = Main.o HelloWorld.o
all: ${objs}
	g++ -o HelloWorld ${objs}

We can even add more variables which may not seem useful now, but are useful later.

CXX = g++
CXXFLAGS =
objs = Main.o HelloWorld.o
Outfile = HelloWorld

all: ${objs}
	${CXX} ${CXXFLAGS} -o ${Outfile} ${objs}

Think about it. Right now you only have one build command, but someday on a huge project you may have dozens and possibly hundreds. Could you imaging changing the CXXFLAGS everywhere? We don’t even have one listed yet, but of course, with the variable you only have to change it once in one place and it will work everywhere you used it.

Adding make clean to your Makefile

It is very common to want to delete all build files and build again. This is often done with the make clean command. But to get make clean to work you have to create a section or label in the make file called clean.

Because we already have variables, it is easy to configure the Makefile to support make clean.

Makefile with clean

CC = g++
CXXFLAGS = -W
objs = Main.o HelloWorld.o
Outfile = HelloWorld

all: ${objs}
	${CC} ${CXXFLAGS} -o ${Outfile} ${objs}

clean:
	rm ${objs} ${outfile}

So simple, we just use rm to delete the files we created, which are all in variables so we had a nice clean short command.

Adding debugging to your make file

There are two schools of thought for debugging.

  • All builds should be release builds unless you run make debug.
  • All builds should be debug builds unless you run make release.

I am not going to tell you which school of thought you should have.  What matters is that you can configure the Makefile to perform how you want it to.

This make file will always build without debugging (release) unless yous specify make debug.

CXX = g++
CXXFlags = -W
objs = Main.o HelloWorld.o
Outfile = HelloWorld

all: objects build

objects: ${objs}

debug: clean
CXXFLAGS += -g
LDFLAGS += -g

debug: objects build

build:
	${CXX} ${CXXFLAGS} -o ${Outfile} ${objs}

clean:
	rm -f ${objs} ${Outfile}

Notice we set LDFLAGS but we never actually call it. It is a special variable that is called automatically by the linker when creating the objects. Yes it must be capitalized.

BSD Licenses good, GPL bad: Microsoft Bans Some Open Source Licenses from WP7 Marketplace

Microsoft is not going to allow GPL onto their phones.
Microsoft Bans Some Open Source Licenses from WP7 Marketplace

Microsoft has stated that its Windows Phone 7 marketplace will reject any apps that use the GPL (GNU General Public License) and similar licenses.

“The Windows Phone Marketplace supports several open source licenses, including BSD, MIT, Apache Software License 2.0, MS-PL and other similar permissive licenses.  We revise our Application Provider Agreement from time to time based on customer and developer feedback, and we are exploring the possibility of modifying it to accommodate additional open source-based applications in upcoming revisions.”

Microsoft is doing the right thing and cannot be blamed in the slightest. The GPL is often termed a viral license and for good reason. Once you use it in your code everything is infected by it. Others say it is a spiderweb license, that once you are in the spider’s web, you can’t get out. The BSD license instead of the GPL is probably the single biggest reason to use FreeBSD over Linux, especially for enterprise business such as Microsoft, Apple, and others.

I don’t like the entrapment of the GPL. Students often first encounter the GPL in college, where they hear that the GPL is free and start using it. Only later do they realize they are trapped. Some don’t mind, wish they would have understood the license better.

Here is a simple rhyme to remember which license to use:

If you want your software to really be free,
    license it with BSD.
If you want your software to be in license hell,
    use the GPL.

This post shows that Microsoft feels the same as many of us who are anti-GPL.

Obviously they don’t want to have those who write their apps ever accidental depend on another app, only to find out the app they depended on is GPL, so their entire work must be GPL as well. They are doing what humanity tries to do with any virus, eradicating it and prevent infection by eliminating the virus, just as we have done with small pox, from the world.

For more information on the differences between the BSD License and the GPL, read this post.
Differences between the BSD/FreeBSD Copyrights and the GNU Public License (GPL)

Russian Government going Open Source…and the future

Well, I have seen governments claim they are going to open source before, but not from Russia, and not with such a realistic plan to migrate over a few years.

Here is a link to the article via Google translate:

Putin ordered the transfer of power on Linux

The now

Business drives software development.  Open Source communities help, but even today much of the ongoing development for Linux is driven by businesses such as Red Hat and Novell and others.  If you think your Linux code is being written by unpaid developers in their spare time, you are somewhat correct but only partially.  Most changes are made by developers who are paid.

While communities are nice, they can’t match the hours or output of experienced developers working forty to sixty hours a week.

Looking Ahead…the Apps…and C# (Mono)

The more open source is used in business, the more development power it will have.  But it is not the open source Operatings Systems that prevent people from moving to Linux or BSD.  Ubuntu, SUSE, Fedora, CentOS, PC-BSD, and numerous others are all very usable desktops that are user friendly.  It is the software that runs on them that everyone is waiting for.

The market is already there to make millions extra if you application runs cross platform, one Windows, MAC, Linux, and BSD.

But most the applications written for Windows, the business desktop of today, are using .NET Framework. So naturally those companies are going to want to make their code cross platform.  And they are going to find it is easier than they thought to move their applications between platforms using C#.  I have recently decided that C# is the future of applications on all platforms.

Some MAC and Linux users don’t like Microsoft and will fight off the idea of a Microsoft provided development platform such as C# (Mono) on their systems.  But when a corporation decides that you must run software X, and software X requires .NET, and you have to either give up your MAC or Linux box for a Windows box, or use C# (Mono), then users will come around.

If you are a company writing software for Windows only today and using C#, you need to take a look at Mono. Even if the return on investment of developing a C# (Mono) based version of your product is a slight loss to break even, it is an investment in the future.  Once written, maintenance costs will be less than the original development costs and that slight loss to break even margin will turn to a small profit.  And with the experience, you next app will migrate to C# (Mono) that much easier and soon, all you apps will run anywhere that C# (Mono) can run.

This is going to take off in a way Java hasn’t because developers for windows prefer and will continue to prefer .NET over Java.  And when it comes to business apps, Java just isn’t the language of choice.  Business applications are written in C#.

FreeBSD or Linux

Ok, so if you have been on my site, you know that I started with Red Hat and never really got into it, and then, settles on FreeBSD.  Why would I choose FreeBSD over Linux? It fit me better.

I actually think that everybody needs to use what suits them.

This is NOT a FreeBSD versus Linux post.  It is a site to help others who are trying to decide whether to use FreeBSD or Linux see some pros and cons and get my recommendation.

FreeBSD

FreeBSD is not Linux or Unix exactly.  It is BSD. It has its own bsd kernel and an is surrounded by a base system.

Here are a list of positives about FreeBSD

  • It is open to proprietary code that just can’t be used in Linux, such as Sun’s ZFS.
  • It is easy to get a small install of just the base system with minimal to no features installed. (Security! Attach surface area is minimized when less software is included.)
  • Jails
  • The ports tree for compiling from source is unmatched by any Linux operating system, but if you prefer binaries, yes, it has them too.
  • Installing software has less problems as you compile it on the system, with the settings you need (rather than get binaries that may have been compiled for a different system or without the settings you need).
  • The documentation is far better than most other open source projects and better than most projects commercial or open source for that matter!
  • OS X chose to use much of FreeBSD in its underlying operating system and so when combining the OS X and FreeBSD market share, FreeBSD code is actually used on more systems than any operating system other than Windows.
  • There are not that many BSD distributions, and the ones that exist have clear focusses different than the others, that later they share.  FreeBSD is a solid server. PC-BSD is a desktop focussed on avoiding dependency problems with its software. OpenBSD is extremely securee. NetBSD is extremely compatible with lots of hardware.  They contribute back to each other often.
  • The License is free and gives everyone who uses it true freedom.
  • The License is free for commercial use.
  • Easy Editor. Newbies can actually use this editor included in the FreeBSD base system.  Don’t forget to learn vi though.
  • Patching is as simple as running freebsd-update.

Here are a list of negatives about FreeBSD

  • Hardware companies tend to make drivers for Windows and Linux first and often don’t include FreeBSD, though most hardware is soon supported.
  • There is not a native Flash Player in FreeBSD, instead the Linux version of Flash must be used.
  • There Desktop options for FreeBSD are not as rich as those for Linux (Example: KDE network settings doesn’t work on FreeBSD, but PC-BSD has their own settings now.)
  • IT/Developers forFreeBSD are harder to come by.

Linux

Linux was originally just a kernel.  The userland was separate.  Now there are plenty of projects that make a nice complete operating system using the Linux kernel and a nice base system surrounding it.

Here are a list of positives about Linux

  • It has a large user base.
  • Free to use.
  • There are plenty of distros to choose from.
  • It is no longer just a kernel but many different groups put out an actual system: Red Hat/Fedora, Debian/Ubuntu, CentOS, SUSE, Arch, Gentoo, etc…
  • A lot of work is going into the desktop environment
  • Development for any Linux platform could benefit all Linux platforms.
  • More and more hardware companies are including Linux drivers
  • Some Software companies make Linux software as well, and the number is increasing
  • Strong commercial backing (which doesn’t make sense for software licensed under the GPL)

Here are some negatives

  • There is often a lot of binary packages that just don’t work.
  • Lack of consolidation.  There are a lot of distributions of Linux and they are not the same. Which one do you choose.
  • Many Linuxes (not all) are now installing desktop software by default, and no longer are minimalistic. (Security! Attach surface area is increased when more software is included.)
  • The inability to write and distribute software that touches GPL software, without having to release your software as GPL too.
  • If you hope to do anything other than use the software or help the community, you need a lawyer to figure out how to interact with the various versions of GPL.
  • The security settings are usually not easy to use and are result in users just turning them off (i.e. SELinux)
  • Are Red Hat and SUSE open source or commercial, they sell support but the software is free, except you can’t get updates without buying support…confusing!
  • IT guys who claim to know Linux usually have done little more than run Ubuntu for a few days.

This is not a flame post and any responses that appear to be trolls will be deleted.

My recommendations

Ok, so what would I recommend if I were paid by a company for consulting?

Server (LAMP)

For a Server running Apache, PHP, SQL, often mis-termed LAMP (Linux Apache MySQL PHP) but really means any OS, Web Server, SQL, Script language.

Recommended OS: FreeBSD

Commerical Appliance

If you work for a company and you need a commercial appliance. Stay away from the dangers of the GPL, just don’t go there.

Recommended OS: FreeBSD

Open Source Desktop

For a quick desktop for a home user that has PC hardware but doesn’t have a license for Windows and doesn’t want to buy one.

Recommended OS: Ubuntu

Note: Sorry PC-BSD friends. Keep working on it.

Commerical Desktop for Employees

If you want a good commercial desktop, you should go with one of the following depending on certain factors, the primary being that some software you may need to use only runs on these two platforms.

Recommended OS: Windows 7 or OS X

However, Ubuntu, Red Hat, SUSE, Fedora, PC-BSD, are all very usable replacements depending on the situation.

Point of Sale (POS) Device

If you need to have to have a POS device for handling sales.

Recommended OS: Depends on needs

Share your thoughts

Hey, please comment.  No flame wars though.  I repeat, this is not a FreeBSD versus Linux post, but a FreeBSD or Linux post, with just some information from my experience. I appreciate all technology and any rude comments will be deleted.  However, feel free to challenge and provide facts, demand facts, etc…

Utah Open Source Conference 2010

Hey all,

The Utah Open Source Conference 2010 was pretty fun.  It was really my first open source conference.  Yes, I have been into open source for 10 years, specifically FreeBSD, but somehow I haven’t really attended the conferences.

I will probably attend conferences more often.

What was there about FreeBSD?

PC-BSD and the folks as iXSystems sent me with some swag.  Howard Logsdon helped me man the GUBUG booth.

There was a great presentation on FreebSD Jails given by Chris Edwards. (http://www.utosc.com/presentation/157/) Supposedly they are going to post a recording of the presentation. Until then, check it here: (http://wiki.zelut.org/doku.php/presentations:freebsd-jails)

Who else was there?

So Novell SUSE brought some nice laptop bags, and they were pretty good.  I have a nice Ogio laptop back pack, so I am giving this laptop bag to my wife.  It is just big enough to fit her 17″ HP laptop.

There was Fedora, Ubuntu, KDE, and GNOME.  There was a boot on XDMC and MythTV.

There was a very cool company there called Fusion-IO.  They have an awesome hard drive, though they are not cheap. 7k for the cheapest drive. But for some companies, it would be worth it.
When is the next Conference?

You can go here to see upcoming events: http://www.freebsd.org/events/events.html

There is the Meet BSD California 2010 conference November 6 and 7th.

To see when the next Utah Open Source Conference is you should go to the site and register so that when the date is announced, you will be informed.