HardenedBSD/contrib/elftoolchain/libdwarf/dwarf_attrval_signed.3
Ed Maste ae500c1ff8 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

226 lines
5.8 KiB
Groff

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.\" $Id: dwarf_attrval_signed.3 3640 2018-10-14 14:09:13Z jkoshy $
.\"
.Dd December 26, 2016
.Dt DWARF_ATTRVAL_SIGNED 3
.Os
.Sh NAME
.Nm dwarf_attrval_flag ,
.Nm dwarf_attrval_signed ,
.Nm dwarf_attrval_string ,
.Nm dwarf_attrval_unsigned
.Nd retrieve the value of an attribute within a DWARF debugging information entry
.Sh LIBRARY
.Lb libdwarf
.Sh SYNOPSIS
.In libdwarf.h
.Ft int
.Fo dwarf_attrval_flag
.Fa "Dwarf_Die die"
.Fa "Dwarf_Half attr"
.Fa "Dwarf_Bool *ret"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_attrval_signed
.Fa "Dwarf_Die die"
.Fa "Dwarf_Half attr"
.Fa "Dwarf_Signed *ret"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_attrval_string
.Fa "Dwarf_Die die"
.Fa "Dwarf_Half attr"
.Fa "const char **ret"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_attrval_unsigned
.Fa "Dwarf_Die die"
.Fa "Dwarf_Half attr"
.Fa "Dwarf_Unsigned *ret"
.Fa "Dwarf_Error *err"
.Fc
.Sh DESCRIPTION
These functions search the debugging information entry referenced
by argument
.Ar die
for the attribute named by argument
.Ar attr .
If the named attribute is found, the functions set the location
pointed to by argument
.Ar ret
to the value of the attribute.
The argument
.Ar err ,
if non NULL,
will be used to return an error descriptor in case of an error.
.Pp
Function
.Fn dwarf_attrval_flag
sets the location pointed to by argument
.Ar ret
to either 0 or 1. If the form of the attribute named by argument
.Ar attr
is
.Dv DW_FORM_flag ,
function
.Fn dwarf_attrval_flag
sets the location pointed to by argument
.Ar ret
to 1 if the attribute has a non-zero value, or to 0 otherwise.
If the form of the attribute named by argument
.Ar attr
is
.Dv DW_FORM_flag_present ,
function
.Fn dwarf_attrval_flag
unconditionally sets the location pointed to by argument
.Ar ret
to 1.
The form of the attribute must be one of
.Dv DW_FORM_flag
or
.Dv DW_FORM_flag_present .
.Pp
Function
.Fn dwarf_attrval_signed
stores the value for the attribute named by argument
.Ar attr ,
into the location pointed to by argument
.Ar ret .
The attribute's value is treated as a signed integral quantity and is
sign-extended as needed.
The attribute named by the argument
.Ar attr
must belong to the
.Dv CONSTANT
class and must have one of the following forms:
.Dv DW_FORM_data1 ,
.Dv DW_FORM_data2 ,
.Dv DW_FORM_data4 ,
.Dv DW_FORM_data8
or
.Dv DW_FORM_sdata .
.Pp
Function
.Fn dwarf_attrval_string
sets the location pointed to by argument
.Ar ret
to a pointer to a NUL-terminated string that is the value of the
attribute named by argument
.Ar attr .
The form of the attribute must be one of
.Dv DW_FORM_string
or
.Dv DW_FORM_strp .
.Pp
Function
.Fn dwarf_attrval_unsigned
stores the value for the attribute named by argument
.Ar attr
into the location pointed to by argument
.Ar ret .
The attribute's value is treated as an unsigned integral quantity, and
is zero-extended as needed.
The named attribute must belong to one of the
.Dv CONSTANT ,
.Dv ADDRESS
or
.Dv REFERENCE
classes and must have one of the following forms:
.Dv DW_FORM_addr ,
.Dv DW_FORM_data1 ,
.Dv DW_FORM_data2 ,
.Dv DW_FORM_data4 ,
.Dv DW_FORM_data8 ,
.Dv DW_FORM_udata ,
.Dv DW_FORM_ref1 ,
.Dv DW_FORM_ref2 ,
.Dv DW_FORM_ref4 ,
.Dv DW_FORM_ref8 ,
or
.Dv DW_FORM_ref_udata .
.Pp
If the attribute named by argument
.Ar attr
is
.Dv DW_AT_type
and is not present in the debugging information entry referenced by argument
.Ar die ,
and if a
.Dv DW_AT_abstract_origin
or
.Dv DW_AT_specification
attribute is present in the debugging information entry,
function
.Fn dwarf_attrval_unsigned
will search for the named attribute in the debugging information entry
referenced by the
.Dv DW_AT_abstract_origin
or
.Dv DW_AT_specification
attribute.
.Sh RETURN VALUES
On success, these functions returns
.Dv DW_DLV_OK .
If the named attribute was not found in the specified debugging
information entry descriptor these functions return
.Dv DW_DLV_NO_ENTRY
and set argument
.Ar err .
For other errors, these functions return
.Dv DW_DLV_ERROR
and set argument
.Ar err .
.Sh COMPATIBILITY
These functions are extensions added by this implementation of the
DWARF(3) API.
.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 the arguments
.Va die
or
.Va ret
was NULL.
.It Bq Er DW_DLE_NO_ENTRY
Argument
.Ar die
did not contain an attribute corresponding to the value in argument
.Ar attr .
.It Bq Er DW_DLE_ATTR_FORM_BAD
The attribute named by argument
.Ar attr
was not of a permitted form.
.El
.Sh SEE ALSO
.Xr dwarf 3 ,
.Xr dwarf_attr 3 ,
.Xr dwarf_hasattr 3