Description
This assignment focuses on using automated build tools such as make. Electronically turn in TWO files:
homework8.txt and Makefile.
Task 1 of 2: Build and Run a Program
Self-Discovery: SourceForge is a useful web site that allows developers to host their open source projects for free.
SourceForge hosts each project’s code and makes it available for any to download free of charge.
For this task you will download, compile, and run a piece of open source software from the web using make. The
program is called jp2a (JPEG to ASCII converter). Here are the steps to follow:
1. Find the jp2a home page using your favorite search engine, and download the program’s source code as a .tar.gz
file from SourceForge. (The download page will have other files available for download, such as a Windows binary
version. You don’t want those files. Click “Browse all files” and look for the .tar.gz file, something like jp2a1.0.6.tar.gz, probably in the 1.0.6 folder inside the jp2a folder)
2. Once you’ve downloaded the file, decompress it into the current directory.
The tar command compresses/decompresses files in the Unix TAR (“tape archive”) file format. TAR merges many
files into a single archive; however, unlike ZIP, TAR does not compress the contents. Therefore most .tar files are
then subsequently also compressed with a separate compression algorithm called GNU ZIP (“gzip”), which yields a
.tar.gz file. (This format was used over ZIP because of patent issues.)
To extract and decompress the jp2a-1.0.6.tar.gz file you will need to figure out the appropriate options to the
tar command, which can be found in the man pages or the lecture slides.
3. After decompressing the archive, change into the directory just created and run the configure program (see note
below) to set up the build process for your particular computer type/architecture. The configure program analyzes
your system and produces a Makefile that will work for your computer to build and install the program.
(Note: The jp2a compilation process requires that your computer have the gcc and make programs and an installed
library called libjpeg. The CSE shared attu server and the CSE VM already have these, but your own Linux
box might not. )
Normally configure sets up the Makefile to install the app to the directory /usr/local/bin, but since you may not
have root access on the system you’re using, you may not be able to install it there. We suggest you tell configure
to install the app to your current directory, the directory where you decompressed the jp2a source files. To do so, run
the command as follows:
./configure –prefix=$(pwd)
If it worked properly, you’ll see several lines of output such as:
checking for a BSD-compatible install… /usr/bin/install -c
config.status: executing depfiles commands
4. Assuming that the configure program completes successfully, you are ready to compile and install the program
using make. Run: make, and once it completes, run: make install . If each command works, it will output
several mostly incomprehensible messages such as:
gcc -g -O2 -o jp2a html.o term.o curl.o jp2a.o image.o -ljpeg -lcurl -lncurses
make[2]: Leaving directory `/homes/iws/zorahf/391/hw8/jp2a-1.0.6/src’
5. If make install worked properly, you should now have a bin/ subdirectory within your jp2a source folder. In
this folder should be a newly built executable called jp2a. You can run the program while in that directory by
typing:
./jp2a [options] filename.jpg
2 of 2
6. In order to make the jp2a command available to you regardless of your current directory you will need to add the
directory that contains the jp2a executable to your PATH. This can be done by adding a line to your bash_profile
that modifies your PATH environment variable. See the lecture slides for how to do this.
If you have done this correctly, the command which jp2a should print the location of the jp2a executable on your
machine. You can also now run the jp2a program from any location on your machine using the following: (note the
./ prefix is no longer required)
jp2a [options] filename.jpg
7. To complete this task you should download a .jpg file of your choice from the web and convert it to ASCII using
jp2a. Use Google Image Search to find an image. You can get the file onto attu by using wget URL if needed.
The jp2a program should output an ASCII version of the image. Redirect the jp2a ASCII output to capture the output
in a file named homework8.txt and submit this file as part of your assignment turnin.
(Side note: jp2a has several options that you can learn by typing jp2a –help. There isn’t a jp2a man page because
we haven’t fully installed the app or its man files into your system. A particularly useful option is —
background=light, which causes white/light backgrounds to be drawn in a lighter color. We found that this option
made the ASCII output of some of our test images, such as a Homer Simpson drawing, look much better.)
Task 2 of 2: Write a Makefile
For this task you will write a Makefile for a small set of C program files provided by the instructor. Download the
resource file hw8.tar.gz from the course web site and decompress it to your homework directory. These files represent
a linked list library stored in linkedlist.c and linkedlist.h along with some client program C files that use this
library to perform simple tasks.
Your Makefile should have the following six properties:
• A target that builds an object file named linkedlist.o from the source code found in linkedlist.c. If
linkedlist.c or linkedlist.h is modified, the linkedlist.o file should be rebuilt. In other words, it depends
on both of those files. (You can test this by touching the .c or .h file and then re-running make.)
• A target that builds an executable file named list_check from the source file use_ll_2.c and the compiled
object file linkedlist.o. If linkedlist.o or any of its dependencies are modified, list_check should be
rebuilt.
• A target that builds an executable file named list_run from the source file use_linkedlist.c and the
compiled object file linkedlist.o. If linkedlist.o or any of its dependencies are modified, list_ run
should be rebuilt. (You can test the list_check and list_run programs by running them once they have been
compiled.)
• A target named clean that removes the list_check and list_ run executables along with any .o files from
the directory.
• The Makefile’s default target (the one that runs if make is not given any parameters) should build both the
list_check and list_run executables.
• Use at least one of make’s advanced features. For example, declare at least one variable and use it in your rules,
and/or try to use some of the special variables such as $^ or $< .
For reference, our Makefile is 16 lines long (11 non-blank, non-comment “substantive” lines).
