UNW_SET_REG(3)						       Programming Library						    UNW_SET_REG(3)

NAME

       unw_set_reg -- set register contents

SYNOPSIS

       #include <libunwind.h>

       int unw_set_reg(unw_cursor_t *cp, unw_regnum_t reg, unw_word_t val);

DESCRIPTION

       The unw_set_reg() routine sets the value of register reg in the stack frame identified by cursor cp to the value passed in val.

       The register numbering is target-dependent and described in separate manual pages (e.g., libunwind-ia64(3) for the IA-64 target).  Further-
       more, the exact set of accessible registers may depend on the type of frame that cp is referring to. For ordinary stack frames, it is  nor-
       mally  possible to access only the preserved (``callee-saved'') registers and frame-related registers (such as the stack-pointer). However,
       for signal frames (see unw_is_signal_frame(3)), it is usually possible to access all registers.

       Note that unw_set_reg() can only write the contents of registers whose values fit in a single word. See unw_set_fpreg(3) for a way to write
       registers which do not fit this constraint.

RETURN VALUE

       On successful completion, unw_set_reg() returns 0.  Otherwise the negative value of one of the error-codes below is returned.

THREAD AND SIGNAL SAFETY

       unw_set_reg() is thread-safe as well as safe to use from a signal handler.

ERRORS

       UNW_EUNSPEC
	       An unspecified error occurred.

       UNW_EBADREG
	       An attempt was made to write a register that is either invalid or not accessible in the current frame.

       UNW_EREADONLY
	       An attempt was made to write to a read-only register.

       In  addition,  unw_set_reg()  may  return any error returned by the access_mem(), access_reg(), and access_fpreg() call-backs (see unw_cre-
       ate_addr_space(3)).

SEE ALSO

       libunwind(3), libunwind-ia64(3), unw_get_reg(3), unw_is_signal_frame(3), unw_set_fpreg(3)

AUTHOR

       David Mosberger-Tang
       Email: dmosberger@gmail.com
       WWW: http://www.nongnu.org/libunwind/.

Programming Library						  16 August 2007						    UNW_SET_REG(3)