dwarf_get_aranges.3

.\" Copyright (c) 2011 Kai Wang
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.\" $Id: dwarf_get_aranges.3 2122 2011-11-09 15:35:14Z jkoshy $
.\"
.Dd November 9, 2011
.Os
.Dt DWARF_GET_ARANGES 3
.Sh NAME
.Nm dwarf_get_aranges
.Nd retrieve program address space mappings
.Sh LIBRARY
.Lb libdwarf
.Sh SYNOPSIS
.In libdwarf.h
.Ft int
.Fo dwarf_get_aranges
.Fa "Dwarf_Debug dbg"
.Fa "Dwarf_Arange **ar_list"
.Fa "Dwarf_Signed *ar_cnt"
.Fa "Dwarf_Error *err"
.Fc
.Sh DESCRIPTION
The function
.Fn dwarf_get_aranges
retrieves address range information from the
.Dq ".debug_aranges"
DWARF section.
Information about address ranges is returned using opaque descriptors
of type
.Vt Dwarf_Arange ,
.Pp
Argument
.Ar dbg
should reference a DWARF debug context allocated using
.Xr dwarf_init 3 .
.Pp
Argument
.Ar ar_list
should point to a location which will be set to a pointer to an array
of
.Vt Dwarf_Arange
descriptors.
.Pp
Argument
.Ar ar_cnt
should point to a location which will be set to the number of
descriptors returned.
.Pp
If argument
.Ar err
is not NULL, it will be used to store error information in case of an
error.
.Ss Memory Management
The memory area used for the array returned in argument
.Ar ar_list
is owned by
.Lb libdwarf .
Application code should not attempt to directly free this area.
Portable applications should instead use
.Xr dwarf_dealloc 3
to indicate that the memory area may be freed.
.Sh RETURN VALUES
Function
.Fn dwarf_get_aranges
returns
.Dv DW_DLV_OK
when it succeeds.
It returns
.Dv DW_DLV_NO_ENTRY
if there is no
.Dq ".debug_aranges"
section associated with the specified debugging context.
In case of an error, it returns
.Dv DW_DLV_ERROR
and sets the argument
.Ar err .
.Sh ERRORS
Function
.Fn dwarf_get_aranges
can fail with:
.Bl -tag -width ".Bq Er DW_DLE_NO_ENTRY"
.It Bq Er DW_DLE_ARGUMENT
One of the arguments
.Ar dbg ,
.Ar ar_list
or
.Ar ar_cnt
was NULL.
.It Bq Er DW_DLE_NO_ENTRY
The debugging context
.Ar dbg
did not contain a
.Dq ".debug_aranges"
string section.
.El
.Sh EXAMPLE
To loop through all the address lookup table entries, use:
.Bd -literal -offset indent
Dwarf_Debug dbg;
Dwarf_Addr start;
Dwarf_Arange *aranges;
Dwarf_Off die_off;
Dwarf_Signed i, cnt;
Dwarf_Unsigned length;
Dwarf_Error de;

if (dwarf_get_aranges(dbg, &aranges, &cnt, &de) != DW_DLV_OK)
	errx(EXIT_FAILURE, "dwarf_get_aranges: %s",
	    dwarf_errmsg(de));

for (i = 0; i < cnt; i++) {
	if (dwarf_get_arange_info(aranges[i], &start, &length,
	    &die_off, &de) != DW_DLV_OK) {
		warnx("dwarf_get_arange_info: %s",
		    dwarf_errmsg(de));
		continue;
	}
	/* Do something with the returned information. */
}
.Ed
.Sh SEE ALSO
.Xr dwarf 3 ,
.Xr dwarf_get_arange 3 ,
.Xr dwarf_get_arange_cu_header_offset 3 ,
.Xr dwarf_get_arange_info 3 ,
.Xr dwarf_get_cu_die_offset 3