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.\" $Id: dwarf_hasform.3 3640 2018-10-14 14:09:13Z jkoshy $
.\"
.Dd May 22, 2010
.Dt DWARF_HASFORM 3
.Os
.Sh NAME
.Nm dwarf_hasform ,
.Nm dwarf_whatform ,
.Nm dwarf_whatform_direct
.Nd query attribute forms
.Sh LIBRARY
.Lb libdwarf
.Sh SYNOPSIS
.In libdwarf.h
.Ft int
.Fo dwarf_hasform
.Fa "Dwarf_Attribute attr"
.Fa "Dwarf_Half form"
.Fa "Dwarf_Bool *ret"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_whatform
.Fa "Dwarf_Attribute attr"
.Fa "Dwarf_Half *retform"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_whatform_direct
.Fa "Dwarf_Attribute attr"
.Fa "Dwarf_Half *retform"
.Fa "Dwarf_Error *err"
.Fc
.Sh DESCRIPTION
Function
.Fn dwarf_hasform
indicates whether the DWARF attribute denoted by argument
.Ar attr
has the attribute form specified by argument
.Ar form .
If the attribute has the specified form, then
argument
.Ar ret
is set to a non-zero value, otherwise it is set to zero.
If argument
.Ar err
is non-NULL, it will be used to return an error descriptor in
case of an error.
.Pp
Function
.Fn dwarf_whatform
sets the location specified by argument
.Ar retform
to the attribute form code for the DWARF attribute referenced
by argument
.Ar attr .
If the attribute referenced by argument
.Ar attr
has an indirect form attribute, this function will return the final
form for the attribute.
If argument
.Ar err
is non-NULL, it will be used to return an error descriptor in
case of an error.
.Pp
Function
.Fn dwarf_whatform_direct
sets the location specified by argument
.Ar retform
to the attribute form code for the DWARF attribute referenced
by argument
.Ar attr .
If the form is an indirect form, the function sets the location
specified by argument
.Ar retform
to
.Dv DW_FORM_indirect .
If argument
.Ar err
is non-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_ERR
and set argument
.Ar err .
.Sh ERRORS
These functions may fail with the following errors:
.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT"
.It Bq Er DW_DLE_ARGUMENT
Any of the arguments
.Ar attr ,
.Ar ret ,
or
.Ar retform
was NULL.
.El
.Sh SEE ALSO
.Xr dwarf 3 ,
.Xr dwarf_attr 3 ,
.Xr dwarf_hasattr 3