gtpc2mfbC/C++ Language Support User's Guide

TO2_getCurrentKey-Retrieve the Current Key

This function allows an application program to retrieve the value of the key being used to access the data element to which the cursor is pointing. This differs from the TO2_key function, which will always return the primary key. The TO2_getCurrentKey function returns either the primary key (if the primary key path is in use) or the appropriate key if an alternate key path is being used to access the data element.

Note:
This function does not support all collections. See Table 48 for collections that are supported for this function.

Format

#include <c$to2.h>
TO2_BUF_PTR TO2_getCurrentKey (const TO2_PID_PTR   cursorPid_ptr,
                                     TO2_ENV_PTR   env_ptr);

cursorPid_ptr
The pointer to the persistent identifier (PID) assigned to the target cursor.

env_ptr
The pointer to the environment as returned by the TO2_createEnv function.

Normal Return

The normal return is a pointer (TO2_BUF_PTR) to a structure (buffer) of type TO2_BUF_HDR (see Type Definitions).

Error Return

An error return is indicated by a zero. When zero is returned, use the TO2_getErrorCode function to determine the specific error code. For more information, see Error Handling.

The following error codes are common for this function:

TO2_ERROR_ENV

TO2_ERROR_METHOD

TO2_ERROR_NOT_INIT

TO2_ERROR_PID

TO2_ERROR_ZERO_PID

Programming Considerations

Examples

The following example retrieves the current access key value of the current data element.

#include <c$to2.h>                /* Needed for TO2 API Functions     */
#include <stdio.h>                /* APIs for standard I/O functions  */
 
TO2_PID          cursor;
TO2_ENV_PTR      env_ptr;
TO2_BUF_PTR      buffer_ptr;      /* Pointer to returned buffer       */
u_char           *key;            /* The key of the element           */

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/**********************************************************************/ /* Retrieve the key from the item pointed to by the cursor. */ /**********************************************************************/ if ((buffer_ptr = TO2_getCurrentKey(&cursor, env_ptr)) == NULL) { printf("TO2_getCurrentkey failed!\n"); process_error(env_ptr); } else { key = buffer_ptr->data; printf("TO2_getCurrrentKey successful!\n"); }
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free (buffer_ptr);

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