xref: /netbsd-src/external/bsd/elftoolchain/dist/libdwarf/dwarf_get_aranges.3 (revision 5ac3bc719ce6e70593039505b491894133237d12)

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.\" Copyright (c) 2011 Kai Wang
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.\" Id: dwarf_get_aranges.3 3962 2022-03-12 15:56:10Z jkoshy
.\"
.Dd November 9, 2011
.Dt DWARF_GET_ARANGES 3
.Os
.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
.Fa dbg
should reference a DWARF debug context allocated using
.Xr dwarf_init 3 .
.Pp
Argument
.Fa ar_list
should point to a location which will be set to a pointer to an array
of
.Vt Dwarf_Arange
descriptors.
.Pp
Argument
.Fa ar_cnt
should point to a location which will be set to the number of
descriptors returned.
.Pp
If argument
.Fa err
is not
.Dv 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
.Fa 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
.Fa err .
.Sh EXAMPLES
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 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
.Fa dbg ,
.Fa ar_list
or
.Fa ar_cnt
was
.Dv NULL .
.It Bq Er DW_DLE_NO_ENTRY
The debugging context
.Fa dbg
did not contain a
.Dq ".debug_aranges"
string section.
.El
.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