$schemamarkup = get_post_meta(get_the_ID(), 'schemamarkup', true); if(!empty($schemamarkup)) { echo $schemamarkup; }

How to Install Linux Kernel Headers on Gnu/Linux Distros

GNU/Linux Installing Kernel Headers Guide

Hi! The Tutorial shows you Step-by-Step How to Install Linux Kernel Headers in GNU/Linux Distributions.

And the Linux Kernel Headers contain the C Header Files for the Linux Kernel.

Which offers the various Function and Structure Definitions required when Compiling any Code that Interfaces with the Kernel, such as Kernel Modules or Device Drivers and some User Programs.

Last, possibly to Install a Custom Kernel with Headers you may see: Installing New Kernel from Source.

How to Install Kernel Headers in Ubuntu - Featured

GNU/Linux Install Linux Kernel Headers Guide