By default Ubuntu doesn’t install the manual pages used for Linux software development which is an invaluable reference for any system developer. These man pages describe the Linux programming interface including Linux system calls as well as system library calls.
To install these man pages simply install the manpages-dev package.

$ sudo apt-get install manpages-dev

You can [...]

For backwards compatibility, many Linux distributions support both the older LinuxThreads implementation as well as the newer Native POSIX Thread Library (NPTL). By setting the LD_ASSUME_KERNEL environment variable you can tell the dynamic linker to assume that it is running on top of a particular kernel version. This will override the dynamic linker’s default [...]