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(3libunwind) for the IA-64 target).  Furthermore, the exact set of accessible registers may
       depend  on  the type of frame that cp is referring to. For ordinary stack frames, it is normally 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(3libunwind)), 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(3libunwind) 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() callbacks (see unw_create_addr_space(3libunwind)).

SEE ALSO

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

AUTHOR

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

Programming Library                              29 August 2023                          UNW_SET_REG(3libunwind)