Software Management

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Software Management
COMP 121-401 UNIX Programming

• Andrew Nashel
• nashel_at_cs.unc.edu
• Department of Computer Science
• January 28, 2004

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On managing software
The structure of a system reflects the structure
of the organization that built it. Richard E.
Fairley Good judgment comes from experience,
and experience comes from bad judgment. Fred
Brooks
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Course topics

• Quiz!
• Software Management
• IDEs
• Make
• Makefiles
• Version control
• CVS
• Core files

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Quiz 1

• No computers, books, or notes.
• 10 minutes.
• Ask me if you have any questions!

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IDEs

• Integrated Development Environments are a
  collection of development tools
• Compiler
• Linker
• Editor
• Debugger
• Project Management

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IDEs Visual Studio
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IDEs - emacs
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What is Make?

• Make is a tools to generate executables from
  source code, based upon the instructions in a
  makefile.
• Make can be used to install, configure and even
  uninstall software. Make is not language
  specific, though the following examples will use
  C/C.

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What is a makefile?

• Makefiles are sets of rules used to build
  targets, by executing a series of commands on the
  source files.
• Basic rule structure
• target dependencies
• commands

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How do you run make?

• When you execute make, you specify a target to
  update (or else it will update the first target
  in the file), and make figures out which inputs
  need to be updated.
• Make uses the makefile to determine which targets
  need to be brought up to date if a target is
  newer than its dependencies, then it is already
  up to date.

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Makefile example

• edit main.o command.o display.o
• cc -o edit main.o command.o display.o
• main.o main.c defs.h
• cc -c main.c
• command.o command.c defs.h command.h
• cc -c command.c
• display.o display.c defs.h buffer.h
• cc -c display.c
• clean
• rm edit main.o command.o display.o

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Making Makefiles easier

• You can use variables as well
• objects main.o command.o display.o
• edit (objects)
• cc -o edit (objects)
• clean
• rm edit (objects)

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Variants of Make

• Make exists on Unix and Windows, and many other
  platforms. The are many variants and extensions
• imake makefile generator
• cmake cross platform make
• Visual Studio projects a type of
  Microsoft-specific makefile

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Source/version control

• Source control or revision control systems are
  tools for one or more developers to track changes
  to source code over time.
• Source control systems include
• SCCS, RCS, CVS, SourceSafe, BitKeeper

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CVS

• Concurrent versions system is a common source
  control system.
• CVS is not a build system it is independent of
  Makefiles, but may contain them. CVS uses RCS to
  track changes to individual files.

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CVS concepts

• A collection of RCS files, called a module, are
  stored in a CVS repository, separate from the
  users files.
• You checkout modules to work on them, modify the
  code and then commit the changes to the
  repository. You can then release (and delete)
  the module.

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What is a core file?

• A core file is created when a program crashes and
  terminates. It contains a snapshot of the
  program memory, which can be used for debugging,
  a.k.a. a core dump.
• You may want to create a non-writable core file
  in your home directory, in case applications
  crash, to prevent core dumps.

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Homework for Fri., Jan 30

• No homework!
• Upcoming topics
• Scripting
• Debugging