Product Documentation

FairCom ISAM for C

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Sets the null key value for the specified index.


NINT ctDECL ctSetNullKeyValue(FILNO keyno, cpTEXT nullkey, ULONG keylen);


  • keyno - the index file number.
  • nullkey - the null key value.
  • keylen - the size of the null key value in bytes, which must be less than or equal to the defined key length, including the tie-breaking bytes for an index that allows duplicates, although those bytes are not considered in the null key comparison. If the null value length is smaller than the key length, only the specified length of the key value is compared to the null key value.


zero on success or a non-zero c-tree error code on failure.

COMPATIBILITY NOTE: An index file that uses this feature, and its corresponding data file, have a feature bit that is set in their header. If this feature bit is set and the server or client or standalone library attempting to open the file does not support this feature, the file open fails with error 744.

See Also