>C defines a virtual machine consisting of a single, contiguous block of memory with consecutive addresses, and a single core processor that reads and executes a single instruction at a time. This is not true of today's processors, thanks to multicores, multiple pipelines, and layers of cache.
Which is true, for a rather stretched definition of "virtual machine"(which falls apart at the kernel level, because it's pretty hard to work with a machine's abstraction when you're working directly on the hardware).
The problem with the virtual machine comparison is that C doesn't mask ABI access in any meaningful way. It doesn't need to, since it's directly accessing the ABI and OS. So the argument that C isn't multithreaded is rather shortsighted, because C doesn't need that functionality in the language. It's provided by the OS.
FYI when discussing the ISO C standard the term "virtual machine" is well understood to be the abstracted view of the hardware presented to user code. Things well defined in it are portable, things implementation defined are non-portable, and things undefined should be avoided at all costs.
Which is true, for a rather stretched definition of "virtual machine"(which falls apart at the kernel level, because it's pretty hard to work with a machine's abstraction when you're working directly on the hardware).
The problem with the virtual machine comparison is that C doesn't mask ABI access in any meaningful way. It doesn't need to, since it's directly accessing the ABI and OS. So the argument that C isn't multithreaded is rather shortsighted, because C doesn't need that functionality in the language. It's provided by the OS.