> For me personally I don't really understand how, if dynamic linking was viral, using linux to run code isn't viral. Surely at some level what linux does to run your code calls GPLed code.
The Linux kernel has an explicit exception for userspace software:
> NOTE! This copyright does not cover user programs that use kernel services by normal system calls
And the GPL also has an explicit exception for "system" software such as kernel, platform libraries etc.:
> The "System Libraries" of an executable work include anything, other
than the work as a whole, that (a) is included in the normal form of
packaging a Major Component, but which is not part of that Major
Component, and (b) serves only to enable use of the work with that
Major Component, or to implement a Standard Interface for which an
implementation is available to the public in source code form. A
"Major Component", in this context, means a major essential component
(kernel, window system, and so on) of the specific operating system
(if any) on which the executable work runs, or a compiler used to
produce the work, or an object code interpreter used to run it.
> The "Corresponding Source" for a work in object code form means all
the source code needed to generate, install, and (for an executable
work) run the object code and to modify the work, including scripts to
control those activities. However, it does not include the work's
System Libraries, or general-purpose tools or generally available free
programs which are used unmodified in performing those activities but
which are not part of the work.
The Linux kernel has an explicit exception for userspace software:
> NOTE! This copyright does not cover user programs that use kernel services by normal system calls