The implementation uses
per default. fcontext_t is based on assembler and not available for all platforms.
It provides a much better performance than
(the context switch takes two magnitudes of order less CPU cycles; see section
As an alternative,
ucontext_t can be used by compiling
ucontext_t might be available
on a broader range of POSIX-platforms but has some disadvantages
(for instance deprecated since POSIX.1-2003, not C99 conform).
Win32-Fibers are used as implementation for call/cc.
Because the TIB (thread information block) is not fully described in the MSDN, it might be possible that not all required TIB-parts are swapped.
The first call of call/cc
converts the thread into a Windows fiber by invoking