gtpc2mf7C/C++ Language Support User's Guide

TO2_cursorMinus-Decrement Cursor to Previous Element

This function decrements the cursor to point to the previous element in the collection.

Format

#include <c$to2.h>
long TO2_cursorMinus (const TO2_PID_PTR cursorPidPtr,
                            TO2_ENV_PTR env_ptr);

cursorPidPtr
The pointer to the cursor persistent identifier (PID) created by one of the TPF collection support (TPFCS) create cursor application programming interfaces (APIs).

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

Normal Return

The normal return is a positive value.

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_CURSOR

TO2_ERROR_ENV

TO2_ERROR_EODAD

TO2_ERROR_METHOD

TO2_ERROR_PID

TO2_ERROR_ZERO_PID

Programming Considerations

Examples

The following example decrements the cursor to point to the previous element in the collection.

#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_ERR_CODE     err_code;        /* TO2 error code value             */
TO2_ERR_TEXT_PTR err_text_ptr;    /* TO2 error code text pointer      */

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/**********************************************************************/ /* Decrement cursor to point to previous element in collection. */ /**********************************************************************/ if (TO2_cursorMinus(&cursor, env_ptr) == TO2_ERROR) { err_code = TO2_getErrorCode(env_ptr); if (err_code != TO2_ERROR_EODAD) { printf("TO2_cursorMinus failed!\n"); process_error(env_ptr); } else printf("Cursor is already positioned at the first element.\n"); } else printf("TO2_atCursorMinus successful!\n");

Related Information

TO2_cursorPlus-Increment Cursor to Next Element.