.\" Copyright (c) 2011 Kai Wang
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.Dd June 26, 2011
.Os
.Dt DWARF_GET_FORM_CLASS 3
.Sh NAME
.Nm dwarf_get_form_class
.Nd retrieve the form class of an attribute
.Sh LIBRARY
.ds str-Lb-libdwarf	DWARF Access Library (libdwarf, -ldwarf)
.Lb libdwarf
.Sh SYNOPSIS
.In libdwarf.h
.Ft enum Dwarf_Form_Class
.Fo dwarf_get_form_class
.Fa "Dwarf_Half dwversion"
.Fa "Dwarf_Half attr"
.Fa "Dwarf_Half offset_size"
.Fa "Dwarf_Half form"
.Fc
.Sh DESCRIPTION
Function
.Fn dwarf_get_form_class
returns the class of the form of a DWARF attribute. 
.Pp
Argument
.Ar dwversion
should specify the version number of DWARF specification
to use: 2 for DWARF2, 3 for DWARF3 and 4 for DWARF4. 
.Pp
Argument
.Ar attr
should hold the attribute code of the attribute, i.e., one of the
.Li DW_AT_*
values defined in
.In libdwarf.h . 
.Pp
Argument
.Ar offset_size
should hold the size of a DWARF offset for the relevant compilation
unit. 
.Pp
Argument
.Ar form
should hold the form code of the attribute. 
.Sh RETURN VALUES
On success, function
.Fn dwarf_get_form_class
returns the form class code, which is one of the
.Dv DW_FORM_CLASS_*
contants defined in header file
.In libdwarf.h . 
If the function was not able to determine the form class of the
attribute, it returns the special form class code
.Dv DW_FORM_CLASS_UNKNOWN . 
.Sh ERRORS
Function
.Fn dwarf_get_form_class
does not return an error. 
.Sh SEE ALSO
.Xr dwarf 3 ,
.Xr dwarf_attr 3 ,
.Xr dwarf_whatattr 3 ,
.Xr dwarf_whatform 3
