#include "btree.h"
int bprvky(BTA* btact, char* key, BTint* value);
The bprvky function returns the previous key
from the current root in the file associated with the
btact context pointer. The key, a
character string, is returned via the pointer in
key. The value associated with the key
will be returned in the integer location identified by
value. value is
declared as a BTint, which is normally a typedef for
int, but with Large File Support will be
a typedef for long long.
bprvky returns zero to indicate the previous
key has been located. If no previous key exists,
bnxtky returns the error code
QNOKEY.
To initialise the B Tree position, a call to bfndky or btpos must be
made before the first call to bprvky.
Thereafter, repeated calls to bprvky may
be made. Calls to bnxtky may be
freely intermingled with calls to bprvky.
A non-zero return from bprvky
indicates an error occurred during the key location process.
