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ucontext(3)

NAME

     ucontext -- user thread context

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <ucontext.h>

DESCRIPTION

     The ucontext_t type is a structure type suitable for holding the context
     for a user thread of execution.  A thread's context includes its stack,
     saved registers, and list of blocked signals.

     The ucontext_t structure contains at least these fields:

	ucontext_t *uc_link	 context to assume when this one returns
	sigset_t uc_sigmask	 signals being blocked
	stack_t uc_stack	 stack area
	mcontext_t uc_mcontext	 saved registers

     The uc_link field points to the context to resume when this context's
     entry point function returns.  If uc_link is equal to NULL, then the
     process exits when this context returns.

     The uc_mcontext field is machine-dependent and should be treated as
     opaque by portable applications.

     The following functions are defined to manipulate ucontext_t structures:

	int getcontext(ucontext_t *);
	int setcontext(const ucontext_t *);
	void makecontext(ucontext_t *, void (*)(void), int, ...);
	int swapcontext(ucontext_t *, const ucontext_t *);

SEE ALSO

     sigaltstack(2), getcontext(3), makecontext(3)

FreeBSD 5.4		      September 10, 2002		   FreeBSD 5.4

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