xref: /netbsd-src/external/bsd/elftoolchain/dist/libdwarf/dwarf_formref.3 (revision 5ac3bc719ce6e70593039505b491894133237d12)

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.\" Id: dwarf_formref.3 3962 2022-03-12 15:56:10Z jkoshy
.\"
.Dd June 21, 2010
.Dt DWARF_FORMREF 3
.Os
.Sh NAME
.Nm dwarf_formref ,
.Nm dwarf_global_formref
.Nd retrieve offsets for REFERENCE class attributes
.Sh LIBRARY
.Lb libdwarf
.Sh SYNOPSIS
.In libdwarf.h
.Ft int
.Fo dwarf_formref
.Fa "Dwarf_Attribute attr"
.Fa "Dwarf_Off *retoffset"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_global_formref
.Fa "Dwarf_Attribute attr"
.Fa "Dwarf_Off *retoffset"
.Fa "Dwarf_Error *err"
.Fc
.Sh DESCRIPTION
These functions return the offsets associated with a DWARF attribute
descriptor.
.Pp
Function
.Fn dwarf_formref
returns the compilation unit relative offset of the descriptor
referenced by argument
.Fa attr
in the location pointed to by argument
.Fa retoffset .
Argument
.Fa attr
must be a reference that is local to a compilation unit.
Permitted forms for argument
.Fa attr
are
.Dv DW_FORM_ref1 ,
.Dv DW_FORM_ref2 ,
.Dv DW_FORM_ref4 ,
.Dv DW_FORM_ref8
and
.Dv DW_FORM_ref_udata .
.Pp
Function
.Fn dwarf_global_formref
returns the section-relative offset of the descriptor referenced by
argument
.Fa attr
in the location pointed to by argument
.Fa retoffset .
Argument
.Fa attr
should be a legal
.Sy REFERENCE
class form.
Permitted forms for argument
.Fa attr
are:
.Dv DW_FORM_ref_addr ,
.Dv DW_FORM_ref_udata ,
.Dv DW_FORM_ref1 ,
.Dv DW_FORM_ref2 ,
.Dv DW_FORM_ref4 ,
.Dv DW_FORM_ref8
and
.Dv DW_FORM_sec_offset .
The returned offset is relative to the start of the
.Dq .debug_info
ELF section.
.Pp
If argument
.Fa err
is not
.Dv NULL ,
it will be used to return an error descriptor in case of an error.
.Sh RETURN VALUES
These functions return
.Dv DW_DLV_OK
on success.
In case of an error, these functions return
.Dv DW_DLV_ERROR
and sets argument
.Fa err .
.Sh ERRORS
These functions may fail with the following errors:
.Bl -tag -width ".Bq Er DW_DLE_ATTR_FORM_BAD"
.It Bq Er DW_DLE_ARGUMENT
Either of arguments
.Fa attr
or
.Fa retoffset
was
.Dv NULL .
.It Bq Er DW_DLE_ATTR_FORM_BAD
The attribute referenced by argument
.Fa attr
was not of a permitted kind.
.El
.Sh SEE ALSO
.Xr dwarf 3 ,
.Xr dwarf_attr 3 ,
.Xr dwarf_formblock 3 ,
.Xr dwarf_formflag 3 ,
.Xr dwarf_formsdata 3 ,
.Xr dwarf_formsig8 3 ,
.Xr dwarf_formstring 3 ,
.Xr dwarf_formudata 3 ,
.Xr dwarf_hasattr 3