FairCom ISAM for C

NextVRecord

Read the next variable-length data record in the data file.

Short Name

NXTVREC()

Type

ISAM function

Declaration

COUNT NextVRecord(COUNT filno, pVOID recptr, pVRLEN plen)

Description

NextVRecord() is identical to it’s fixed-length counterpart, NextRecord(), except that it reads the next variable-length data record. If successful, this record becomes the current ISAM record for the associated data file.

plen acts as both an input and output parameter:

On input, plen contains the length of the output buffer.
On output, the contents of plen is the actual data-record length. If the length of the output buffer is less than the actual record length, a partial read is performed. If an error occurs, plen is unspecified.

Read the function description for NextRecord() for additional important information.

As of c-tree V8.14, c-tree sets the current ISAM position after a record is added such that the next or previous record can be read without having to re-read the record just added. Prior to V8.14, the current ISAM position was not set to a newly-added record and an INOT_ERR (101) error would result if you tried to read either the next or previous record.

Return

Value	Symbolic Constant	Explanation
0	NO_ERROR	Successful retrieval of current ISAM record.
633	NPLN_ERR	plen is NULL.
634	NLEN_ERR	plen is negative on input.

See c-tree Error Codes for a complete listing of valid c-tree error values.