Manual browser: dwarf_var_die_offset(3)

DWARF_GET_VARS(3)

Library Functions Manual

DWARF_GET_VARS(3)

NAME

dwarf_get_vars, dwarf_var_cu_offset, dwarf_var_die_offset, dwarf_var_name_offsets, dwarf_varname — retrieve information about static variables

LIBRARY

DWARF Access Library (libdwarf, -ldwarf)

SYNOPSIS

#include <libdwarf.h>

int
dwarf_get_vars(Dwarf_Debug dbg, Dwarf_Var **vars, Dwarf_Signed *nvars, Dwarf_Error *err);

int
dwarf_var_cu_offset(Dwarf_Var var, Dwarf_Off *cu_offset, Dwarf_Error *err);

int
dwarf_var_die_offset(Dwarf_Var var, Dwarf_Off *die_offset, Dwarf_Error *err);

int
dwarf_var_name_offsets(Dwarf_Var var, char **name, Dwarf_Off *die_offset, Dwarf_Off *cu_die_offset, Dwarf_Error *err);

int
dwarf_varname(Dwarf_Var var, char **name, Dwarf_Error *err);

DESCRIPTION

These functions retrieve information about the file scope static variables associated with a DWARF debug context. Information about these static variables is returned using opaque descriptors of type Dwarf_Var. Applications need to use the functions described below to retrieve the name and offset information contained in these descriptors.

Function dwarf_get_vars() retrieves descriptors for all the static variables associated with the DWARF debug context specified by argument dbg. The argument vars should point to a location that will be set to a pointer to an array of Dwarf_Var descriptors. The argument nvars should point to a location that will be set to the number of descriptors returned.

Function dwarf_var_cu_offset() returns the section-relative offset, relative to the “.debug_info” section, of the compilation unit that contains the debugging information entry associated with the argument var. Argument cu_offset should point to a location that will hold the returned offset.

Function dwarf_var_die_offset() retrieves the section-relative offset, relative to the “.debug_info” section, of the debugging information entry associated with the argument var, and stores it into the location pointed to by the argument die_offset.

Function dwarf_var_name_offsets() retrieves both the name and the associated offsets for the debugging information entry for argument var. Argument name should point to a location which will be set to a pointer to a NUL-terminated string containing the name of the associated debugging information entry. Argument die_offset should point to a location which will be set to a section-relative offset, relative to the “.debug_info” section, of the associated debugging information entry. Argument cu_die_offset should point to a location which will be set to a section-relative offset, relative to the “.debug_info” section, of the first debugging information entry in the compilation unit associated with argument var.

Function dwarf_varname() sets the location pointed to by argument name to a pointer to a NUL-terminated string holding the name of the debugging information entry associated with the argument var.

Memory Management

The memory area used for the array of Dwarf_Var descriptors returned in argument vars by function dwarf_get_vars() is owned by the DWARF Access Library (libdwarf, -ldwarf). Application code should not attempt to directly free this pointer. Portable code should instead use the function dwarf_vars_dealloc(3) to indicate that the memory area may be freed.

The memory area used for the string returned in the name argument to functions dwarf_var_name_offsets() and dwarf_varname() is owned by the DWARF Access Library (libdwarf, -ldwarf). Portable code should indicate that the memory area can be freed using the dwarf_dealloc(3) function.

Error Returns

If argument err is not NULL, these functions will use it to store error information, in case of an error.

RETURN VALUES

On success, these functions returns DW_DLV_OK. In case of an error, they return DW_DLV_ERROR and set the argument err.

ERRORS

These functions may fail with the following errors: