FairCom ISAM for C

CurrentISAMKey

Create an ISAM key from the current ISAM record.

Short Name

GETCURK()

Type

ISAM function

Declaration

pVOID CurrentISAMKey(FILNO keyno, pVOID idxval, pVRLEN plen);

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

CurrentISAMKey() looks at the current ISAM key buffer for index file keyno and creates a well formed ISAM key. This key is placed at idxval. The length of the key is placed at plen, if plen is not NULL. The ISAM key created with CurrentISAMKey() includes the 4-byte or 8-byte suffix for duplicate keys.

Return

CurrentISAMKey() returns a pointer to the key value. A NULL signifies an error or no current key exists.

Warning: The key buffer is filled with garbage when the return value is NULL on server calls, but non-server calls do not touch the key buffer on NULL returns. Check isam_err for the following error codes on a NULL return.

Value	Symbolic Constant	Explanation
0	NO_ERROR	Successful retrieval of current ISAM record.
22	FNUM_ERR	keyno out of range.
26	FACS_ERR	keyno is not active.
48	FMOD_ERR	keyno does not reference an index file.

See FairCom DB Error Codes for a complete listing of valid FairCom DB error values.

Example

FILNO keyfil;

TEXT keybuf[50];

VRLEN keylen;

if (CurrentISAMKey(keyfil,&keybuf,&keylen) == NULL)

printf("\nError %d with file %d",isam_err,isam_fil);

Limitations

No check is made to determine if idxval points to a region sufficiently large to accept a key. If the area is too small, either code or data will be clobbered. Use GetCtFileInfo() to obtain the key length.

Note, the key value returned by this function will be a properly formatted key value (i.e., HIGH_LOW order, forced to upper case, etc.). The main issue this presents is if binary key values will be displayed on a LOW_HIGH machine, it will be necessary to reverse any numeric segments.