Metrologic Optimus R, Programming Manual

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Chapter 3 Terminal Specific Function Library 209
tell_DBF
Purpose To get the current index pointer position of an IDX file.
Syntax long tell_DBF (int DBF_fd, int key_number);
int DBF_fd; /* file handle of the associated DBF file */
int key_number; /* key number of the target IDX file */
Example rank_number = tell_DBF (DBF_fd, 1);
Description This routine gets the current index pointer position of an IDX file
(
key_number
), which is associated with a DBF file (
DBF_fd
).
The index pointer position is expressed in rank number in the IDX file. For
example, if the index pointer points to the first index, its position will be
1L.
Return If successful, it returns the rank number for the current index pointer.
On error, it returns -1L.
An error code is set to the global variable fErrorCode to indicate the error
condition encountered. Below are possible error codes and their interpretation.
Error Code Interpretation
2 File specified by
DBF_fd
does not exist.
4 File specified by DBF_fd is not a DBF file.
7 Invalid file handle.
8 File not opened.
13 Invalid value in argument: key_number
14 IDX file specified by key_number does not exist.
See Also
lseek_DBF
update_member
Purpose To update a data record (member) of a DBF file.
Syntax int update_member (int DBF_fd, int key_number, char *member);
int DBF_fd; /* file handle of the target DBF file */
int key_number; /* key number of the associated IDX file */
char *member; /* pointer to a buffer holding the member to be updated */
Example update_member (DBF_fd, 1, 10);
Description This routine updates a data record ( member ) pointed to by the index pointer of
an IDX file (
key_number
), which is associated to a DBF file (
DBF_fd
).
Return If successful, it returns 1.
On error, it returns 0.