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I386_SET_WATCH(3)	 BSD Library Functions Manual	     I386_SET_WATCH(3)

NAME
     i386_clr_watch, i386_set_watch -- manage i386 debug register values

LIBRARY
     Standard C	Library	(libc, -lc)

SYNOPSIS
     #include <machine/reg.h>
     #include <machine/sysarch.h>

     int
     i386_clr_watch(int	watchnum, struct dbreg *d);

     int
     i386_set_watch(int	watchnum, unsigned int watchaddr, int size,
	 int access, struct dbreg *d);

DESCRIPTION
     The i386_clr_watch() function will	disable	the indicated watch point
     within the	specified debug	register set.

     The i386_set_watch() function will	set up the specified debug registers
     as	indicated by the arguments.  The watchnum argument specifies which
     watch register is used, 0,	1, 2, 3, or -1.	 If watchnum is	-1, a free
     watch register is found and used.	If there are no	free watch registers,
     an	error code of -1 is returned.  The watchaddr argument specifies	the
     watch address, size specifies the size in bytes of	the area to be watched
     (1, 2, or 4 bytes), and access specifies the type of watch	point:

	   DBREG_DR7_EXEC    An	execution breakpoint.
	   DBREG_DR7_WRONLY  Break only	when the watch area is written to.
	   DBREG_DR7_RDWR    Break when	the watch area is read from or written
			     to.

     Note that these functions do not actually set or clear breakpoints; they
     manipulate	the indicated debug register set.  You must use	ptrace(2) to
     retrieve and install the debug register values for	a process.

RETURN VALUES
     On	success, the i386_clr_watch() function returns 0.  On error, -1	re-
     turned which indicates that watchnum is invalid (not in the range of
     0-3).  If the specified watchnum was already disabled, no error is	re-
     turned.

     On	success, the i386_set_watch() function returns the watchnum argument,
     or	the watchnum actually used in the case where the specified watchnum
     was -1.  On error,	the i386_set_watch() function returns -1 indicating
     that the watchpoint could not established because either no more watch-
     points are	available, or watchnum,	size, or access	is invalid.

SEE ALSO
     ptrace(2),	procfs(5)

AUTHORS
     This man page was written by Brian	S. Dean.

BSD				August 24, 2000				   BSD
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | SEE ALSO | AUTHORS

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