MPE/iX Intrinsics Reference Manual (32650-90905)

190 Chapter5
Command Definitions (FCONTROL - FLOCK)
FFINDN
FFINDN
NM and CM callable.
Positions the logical record pointer to the relative record number according to the key
sequence.
NOTE For KSAM files only.
Syntax
I16V DV I16V
FFINDN(
filenum,number,location );
Parameters
filenum 16-bit signed integer (required)
Passes the file number of the file to be positioned.
number double by value (required)
Specifies a record number relative to the first logical record in the file.
Record numbers start with zero or one depending on the record numbering
scheme specified at file creation. The lowest numbered record applies to
the record with the lowest value in the specified key field. A negative
record number positions the file pointer to the record with the smallest key
value.
location 16-bit signed integer by value (required)
Passes the relative byte location in the record of the key to be used. The
first byte of the record is considered 1. If
location =0, the primary key is
used.
Operation Notes
Split stack calls are permitted.
When the relative record number is specified, be sure not to confuse this number with the
chronological record number (the number of the record as it is stored in the file). The
relative record number is based on the value of a specified key, not its location in a file.
(KSAM/3000) If FFINDN is used to position the pointer before calling another procedure
that reads or updates the file in a shared environment, FLOCK must be called before calling
FFINDN. After performing the read or update operation, unlock the file. If the file is locked
after calling FFINDN, another user can change the pointer position without your program
being aware of it.