FairCom ISAM for C

VDataLength

Get length of variable-length data record.

Short Name

GTVLEN()

Type

Low-Level variable-length data file function

Declaration

VRLEN VDataLength(FILNO datno, LONG recbyt)

Description

In V12 the file number typedef was formally changed from COUNT, a two-byte value to FILNO, a four-byte value. Refer to this link for compatibility details. Four Byte File Numbering

VDataLength() returns the total length of the variable-length data record beginning at byte offset recbyt in file datno.

Return

If no error occurs, VDataLength() returns the total record length for the specified offset. When VDataLength() returns a zero, check uerr_cod. If uerr_cod is zero, the record length is zero. Otherwise, an error occurred as follows:

Value	Symbolic Constant	Explanation
0	NO_ERROR	Successful operation.
29	ZREC_ERR	Data file routine called with recbyt = 0.
48	FMOD_ERR	Operation incompatible with type of file. The specifics vary by function: The specified keyno is not an index file number. The file is not a data file or it does not contain an IFIL resource (ctFILBLK in ctFBisam mode). One or more associated file (data and index files) is not TRANDEP (using RENIFIL / RENIFILX).
149	VRLN_ERR	Variable-length passed to AddVRecord() is less than minimum record length established at file creation.
154	VRCL_ERR	Attempt to read (R) a zero length record from a variable-length data file.
158	VFLG_ERR	ReReadVRecord() record not marked active.

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

Example

LONG pntr;

VRLEN vreclen;

FILNO datno,keyno;

TEXT key_buffer[64];

if ((pntr = FirstKey(keyno,key_buffer)) != 0L) {

vreclen = VDataLength(datno,pntr);

if (uerr_cod == 0) {

if (vreclen)

printf(

"\nFirst variable record by key requires %d bytes",

vreclen);

else

printf("\nRecord length is zero.");

}

else

printf("\nError %d getting length.", uerr_cod);

}