TBLT_RETC TBLT_ENTRY BltDataMarkRecord(TBLT_DH *dhPtr, ULONG recNo, ULONG tagChar); dhPtr IO:data file control structure recNo I:number of record to remove tagChar I:byte to set tag characterThis routine marks a data record's tag byte (the first byte of the record) with the tagChar byte.
Data records are not physically removed when deleted. Instead, records are
tagged, or marked, as being deleted and then later removed by using
BltDataPack()
. The first byte of each data record is reserved for
this byte. (Your first field starts at the second byte of the data record.)
The standard markers for this are <space> (a blank, ASCII 32) and *
(a
star, ASCII 42). The space indicates that the record is not deleted, and a
star indicates that the record is deleted (marked as deleted, that is).
Two C macros are included if explicit delete and undelete names are needed. Supply the dhPtr and recNo args, leaving the tagChar to be set by the macro.
#define BltDataDeleteRecord(a,b) BltDataMarkRecord(a,b,42) #define BltDataUndeleteRecord(a,b) BltDataMarkRecord(a,b,32)Since your program has control of the entire data record already, this routine is not necessary; you may just set the first byte of your record as you want. However, you must still reserve this first byte for this use.
Return: Non-zero indicates an error, otherwise the first byte of the record is set
to tagChar.