Metrologic Optimus R, Руководство по программированию

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204 "C" Programming Guide For Optimus S/R
8 File not opened.
13 Invalid value in argument: key_number
14 IDX file specified by key_number does not exist.
16 No members exist in the DBF file.
See Also has_member
has_member
Purpose To check if a data record (member) exists in a DBF file.
Syntax
int has_member (int DBF_fd, int key_number, char *key_value);
int DBF_fd; /* file handle of the target DBF file */
int key_number;
/* key no. of the IDX file whose pointer points to the target member */
char *key_value;
/* pointer to a buffer holding key value to identify a specific member */
Example if (has_member (DBF_fd, 1, "JOHN")) puts ("JOHN is on the name list!\n");
Description This routine tries to locate a data record that matches the key value in an IDX
file (
key_number
), which is associated to a DBF file (
DBF_fd
).
If there is a complete match to the key_value, the index pointer will point
to the first of all matches.
In case there is more than one member containing the key value, user can
then check each member sequentially from the one currently is pointed to
by the index pointer until the desired member is found.
Return If a member exists, it returns 1.
If a member does not exist, it returns 0.
On error, it returns -1.
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 get_member