A Beginner's Guide to Compiling Source Code

 in
If you've been hesitant to compile Linux source code, hesitate no more—this article gives complete instructions for your first foray.
A Few Hints

In several instances I've failed miserably with a source distribution, then weeks or months later downloaded a later version and had it compile cleanly. Perhaps I updated a library the Makefile was looking for, or perhaps the author made a change in the source which fortuitously caused the program to be compatible with my system. In other words, it's worthwhile to try again later when you initially have a problem.

Another situation I've found myself in: after several edits of the Makefile and perhaps a few header files I'm getting more and more compiler errors. Nothing seems to work and I can't seem to make any headway. This is an ideal time to delete the entire directory tree and reinstall it from the archive file. Sometimes a completely fresh start helps.

One compiler flag to watch out for in the Makefile is -g (as in gcc -g). The GNU programs often have this flag, which instructs the compiler to add bulky debugging code to the executable. This is needed if you plan to use a debugger on the program. I don't even have a debugger installed, so I routinely remove that flag. The strip utility will remove this debugging code, often reducing an executable to half its original size.

Virtual consoles are tailor-made for compiling. Once you've set a lengthy compilation in motion, just switch to another console and start something else. I like to shut down X-Windows while compiling, as gcc uses all of the processor cycles it can get. The more resources that are available, the faster your program will compile.

Conclusion

So what do you gain from learning to compile programs?

  • The range of software available to you is considerably increased.

  • I believe there is an advantage to using an executable tuned to your system and configuration.

  • You have the opportunity to specify compiler flags, like >\#140>O2, to optimize the code. Sometimes there are compile-time options that can be set or unset in the Makefile.

  • Functions or subroutines in the program you know you will never need can be left out of the executable.

  • Source code is often the only form in which successive builds are available in beta-testing scenarios.

  • Often more complete documentation will be included with source code than with a binary distribution.

  • It is interesting to get glimpses into the way programs are put together. Often source files are heavily commented, because the programmer might want to explain sections of code to present or future collaborators in the project.

Larry Ayers (layers@vax2.rain.gen.mo.us) lives on a small farm in norther Missouri, where he is currently engaged in building a timber-frame house for his family. He operates a portable band-saw mill, does general woodworking, plays the fiddle and searches for rare prairie plants, as well as growing shiitake mushrooms. He is also struggling with configuring a Usenet news server for his local ISP.

______________________

Comments

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

The article had nothing that

Anonymous's picture

The article had nothing that would help anybody to compile anything. You are only explaining the technology. The title is very misleading.

Webinar
One Click, Universal Protection: Implementing Centralized Security Policies on Linux Systems

As Linux continues to play an ever increasing role in corporate data centers and institutions, ensuring the integrity and protection of these systems must be a priority. With 60% of the world's websites and an increasing share of organization's mission-critical workloads running on Linux, failing to stop malware and other advanced threats on Linux can increasingly impact an organization's reputation and bottom line.

Learn More

Sponsored by Bit9

Webinar
Linux Backup and Recovery Webinar

Most companies incorporate backup procedures for critical data, which can be restored quickly if a loss occurs. However, fewer companies are prepared for catastrophic system failures, in which they lose all data, the entire operating system, applications, settings, patches and more, reducing their system(s) to “bare metal.” After all, before data can be restored to a system, there must be a system to restore it to.

In this one hour webinar, learn how to enhance your existing backup strategies for better disaster recovery preparedness using Storix System Backup Administrator (SBAdmin), a highly flexible bare-metal recovery solution for UNIX and Linux systems.

Learn More

Sponsored by Storix