freebsd-skq/contrib/elftoolchain/libdwarf/dwarf_attr.3
emaste b54d7a9715 Update to ELF Tool Chain r3668
Highlights:
- Make sure that only TLS sections are sorted into TLS segment.
- Fixed multiple errors in "Section to Segment mapping".
- Man page updates
- ar improvements
- elfcopy: avoid filter_reloc uninitialized variable for rela
- elfcopy: avoid stripping relocations from static binaries
- readelf: avoid printing directory in front of absolute path
- readelf: add NT_FREEBSD_FEATURE_CTL FreeBSD note type
- test improvements

NOTES:

Some of these changes originated in FreeBSD and simply reduce diffs
between contrib and vendor.

ELF Tool Chain ar is not (currently) used in FreeBSD, and there are
improvements in both FreeBSD and ELF Tool Chain ar that are not in
the other.

Sponsored by:	The FreeBSD Foundation
2019-01-10 14:35:23 +00:00

122 lines
3.3 KiB
Groff

.\" Copyright (c) 2010 Kai Wang
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.\" $Id: dwarf_attr.3 3644 2018-10-15 19:55:01Z jkoshy $
.\"
.Dd April 8, 2010
.Dt DWARF_ATTR 3
.Os
.Sh NAME
.Nm dwarf_attr
.Nd retrieve an attribute descriptor associated with a DWARF debugging information entry
.Sh LIBRARY
.Lb libdwarf
.Sh SYNOPSIS
.In libdwarf.h
.Ft int
.Fo dwarf_attr
.Fa "Dwarf_Die die"
.Fa "Dwarf_Half attr"
.Fa "Dwarf_Attribute *atp"
.Fa "Dwarf_Error *err"
.Fc
.Sh DESCRIPTION
Function
.Fn dwarf_attr
retrieves the attribute descriptor for an attribute associated
with the DWARF debugging information entry descriptor in
argument
.Ar die .
.Pp
DWARF attribute descriptors are represented by value of the opaque
type
.Vt Dwarf_Attribute ,
see
.Xr dwarf 3 .
.Pp
Argument
.Ar attr
names the desired DWARF attribute.
Legal values for argument
.Ar attr
are those denoted by the
.Dv DW_AT_*
constants in the DWARF specification.
.Pp
Argument
.Ar atp
points to a location into which the returned attribute descriptor
will be written.
The returned descriptor may then be passed to the form query functions in the
.Xr dwarf 3
API set to access the data associated with the attribute.
.Pp
If argument
.Ar err
is non-NULL, it will be used to return an error descriptor in case
of an error.
.Sh RETURN VALUES
Function
.Fn dwarf_attr
returns
.Dv DW_DLV_OK
on success.
.Pp
If the debugging information entry descriptor denoted by argument
.Ar die
does not contain the named attribute, the function returns
.Dv DW_DLV_NO_ENTRY
and sets argument
.Ar err .
For other errors, it returns
.Dv DW_DLV_ERROR
and sets argument
.Ar err .
.Sh ERRORS
Function
.Fn dwarf_attr
can fail with the following errors:
.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT"
.It Bq Er DW_DLE_ARGUMENT
Either of arguments
.Ar die
or
.Ar atp
was NULL.
.It Bq Er DW_DLE_NO_ENTRY
Argument
.Ar die
had no attribute corresponding to the value
in argument
.Ar attr .
.El
.Sh SEE ALSO
.Xr dwarf 3 ,
.Xr dwarf_attrlist 3 ,
.Xr dwarf_attroffset 3 ,
.Xr dwarf_hasattr 3 ,
.Xr dwarf_hasform 3 ,
.Xr dwarf_whatattr 3 ,
.Xr dwarf_whatform 3