Product Documentation

FairCom ISAM for C

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  • Without key buffer support the application cannot perform updates to the file, including adds, deletes, or re-writes. Updates require key buffers. Attempting to do so returns error KBUF_ERR (121).
  • Unlike the previous UpdateHeader() modes, this mode does not make a permanent change to the file header, does NOT require the file to be opened exclusively, and applies only to the user making the call.
  • UpdateHeader(...,ctISAMKBUFhdr) returns FMOD_ERR (48) when called for an index file.
  • When the key buffer support is turned off, the current ISAM position for the data file is set to zero which implies no current ISAM position.
  • If the key buffer support is off, one cannot traverse a file by one key and perform a NextRecord() or PreviousRecord() for a different key. Only the key that established the ISAM position, through calls such as FirstRecord(), GetRecord(), or GetGTERecord(), can be used in NextRecord() or PreviousRecord(). If the data file is traversed in physical order, no ISAM key buffer is supported.

See UpdateHeader (UpdateHeader, UpdateHeader).