Using and Administering

ll_get_data Subroutine

Before you use this subroutine, make sure you are familiar with Understanding the LoadLeveler Job Object Model.

Purpose

The ll_get_data subroutine returns data from a valid LL_element.

Library

LoadLeveler API library libllapi.a

Syntax

  #include "llapi.h"
 
  int ll_get_data(LL_element *element, enum LLAPI_Specification specification,
  void* resulting_data_type);

Parameters

element

Is a pointer to the LL_element returned by the ll_get_objs subroutine or by the ll_get_data subroutine. For example: Job, Machine, Step, etc.

specification

Specifies the data field within the data object you want to read.

resulting_data_type

Is a pointer to where you want the data stored. If this parameter is equal to NULL, then an error has occurred and the value could not be stored.

Description

object and specification are input fields, while resulting_data_type is an output field.

The ll_get_data subroutine of the data access API allows you to access LoadLeveler objects. The parameters of ll_get_data are a LoadLeveler object (LL_element), a specification that indicates what information about the object is being requested, and a pointer to the area where the information being requested should be stored.

If the specification indicates an attribute of the element that is passed in, the result pointer must be the address of a variable of the appropriate type, and must be initialized to NULL. The type returned by each specification is found in Table 15. If the specification queries the connection to another object, the returned value is of type LL_element. You can use a subsequent ll_get_data call to query information about the new object.

The data type char* and any arrays of type int or char must be freed by the caller.

LL_element pointers cannot be freed by the caller.

When using the 2.1.0 release APi of ll_get_data, you must use the new 2.1 release keywords. For instance, you can not use the min_processors and max_processors from the 1.3.0 release with the 2.1 release API ll_get_data. You must use the new keyword, node.

Return Values

This subroutine returns a zero to indicate success.

Error Values

-1

You specified an invalid object.

-2

You specified an invalid LLAPI_Specification.

Related Information

Subroutines: ll_query, ll_set_request, ll_reset_request, ll_get_objs, lL_next_obj, ll_free_objs, ll_deallocate.