DWARF_GET_VARS(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:

[`DW_DLE_ARGUMENT`]
  One of the arguments cu_die_offset, cu_offset, dbg, die_offset, var, vars, name, or nvars was `NULL`.

# SEE ALSO

dwarf(3), dwarf_dealloc(3), dwarf_get_cu_die_offset_given_cu_header_offset(3), dwarf_vars_dealloc(3)

April 2, 2011 | NetBSD 10.0