ProgrammingThis forum is for all programming questions.
The question does not have to be directly related to Linux and any language is fair game.
Notices
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month. Click here for more info.
Could someone tell me why linux has many header files in the /usr/include direcory with an identically named file in the /usr/include/bits directory. For example, if one wants to see a definition of the termios struct it isn't in /usr/include/termios.h, but in /usr/include/bits/termios.h. Of course, there is an #include <bits/termios.h> statement in termios.h, but why are there two files?
All standard C++ headers are supposed to be .h-less. The names of the headers and behaviors of the classes are specified in the C++ standard, however the implementation is left up to the lib author. Most of the headers are for templates and therefore include some source code, and many of the includes include multiple bits headers (such as constants and settings that have separate files.) Basically, the main directory is for the standard-compliant file names, and the bits subdirectory allows the developers to manage the code in whatever manner they choose.
ta0kira
The bits sub-directory is there to support diffent "endianness", for one thing.
In other words, it is system-specific. If you go to a big endian system or a little endian system the same filenames will be there. What's in them will be different.
The /usr/include/sys subdirectory does the same thing. You'll notice that stat.h is in sys because how it works is usually system-specific.
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know.