NAME

dwarf_attrlist — retrieve DWARF attribute descriptors

LIBRARY

DWARF Access Library (libdwarf, -ldwarf)

SYNOPSIS

#include <libdwarf.h>

int
dwarf_attrlist(Dwarf_Die die, Dwarf_Attribute **attrbuf, Dwarf_Signed *attrcount, Dwarf_Error *err);

DESCRIPTION

Function dwarf_attrlist() retrieves the DWARF attribute descriptors associated with a debugging information entry descriptor in argument die. The descriptors are returned as an array of values of the opaque type Dwarf_Attribute. The data associated with each returned attribute descriptor may be queried using the form query functions in the dwarf(3) API set.

Argument attrbuf points to a location that will hold a pointer to the returned array of DWARF attribute descriptors. Argument attrcount points to a location that will hold the number of descriptors in the returned array.

If argument err is non-NULL, it is used to return an error descriptor in case of an error.

Memory Management

In the current implementation, the memory allocated for each DWARF attribute descriptor and for the returned array of descriptors is managed by the library and the application does not need to explicitly free the returned pointers. However, for compatibility with other implementations of the dwarf(3) API, the application is permitted to pass the pointers returned by to the dwarf_dealloc() function.

RETURN VALUES

Function dwarf_attrlist() returns DW_DLV_OK on success.

If the debugging information entry descriptor denoted by argument die does not contain any attribute, the function returns DW_DLV_NO_ENTRY and sets argument err. For other errors, it returns DW_DLV_ERROR and sets argument err.

EXAMPLES

To retrieve the attribute list for a DWARF debugging information entry use:

Dwarf_Die dw_die;
Dwarf_Error dw_e;
Dwarf_Unsigned dw_count;
Dwarf_Attribute *dw_attributes;
int error, i;

... variable dw_die contains a reference to the DIE of interest ...

/* Retrieve the attribute list from the DIE. */
if ((error = dwarf_attrlist(dw_die, &dw_attributes, &dw_count,
	&dw_e)) != DW_DLV_OK)
	errx(EXIT_FAILURE, "dwarf_attrlist: %s", dwarf_errmsg(dw_e));

/* Process the attribute list. */
for (i = 0; i < dw_count; ++i) {
	/* Use the returned pointers in dw_attributes[i] here. */
}

ERRORS

Function dwarf_attrlist() can fail with the following errors:

[DW_DLE_ARGUMENT]: Arguments die, attrbuf, or attrcount were NULL.
[DW_DLE_NO_ENTRY]: Argument die had no attributes.
[DW_DLE_MEMORY]: An out of memory condition was encountered during the execution of the function.