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GetGTKey
Search index file for entry greater than target.
Short Name
GTKEY()
Type
Low-Level index file function
Declaration
LONG GetGTKey(FILNO keyno, pVOID target, pVOID idxval)
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
GetGTKey() searches index file keyno for the first entry that is strictly greater than the key value pointed to by target. If such an entry exists, then it is copied into the area pointed to by idxval.
Return
If GetGTKey() is successful, it returns the data record position associated with the entry found in the index. If an error occurs or no such entry exists, (either the index is empty, or the target key value exceeds all entries in the index), then GetGTKey() returns a zero. When GetGTKey() returns a zero check the value of uerr_cod: if uerr_cod is non-zero, an error was detected; otherwise, no key value satisfied the search. See FairCom DB Error Codes for a complete listing of valid FairCom DB error values.
Example
FILNO keyno;
TEXT target[24],idxval[23];
LONG recbyt;
ctsfill(target,0,24);
ctsfill(idxval,0,23);
scanf("%23s",target);
recbyt = GetGTEKey(keyno,target,idxval);
while (recbyt) {
printf("\nIndex entry = %23s Record # = %ld",
idxval,recbyt);
cpybuf(target,idxval,23);
recbyt = GetGTKey(keyno,target,idxval);
}
Limitations
No check is made to determine if idxval points to a region sufficiently large to accept a key value from the index file. If the area is too small, either code or data will be clobbered.
The key value returned 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.
The recbyt parameter in this function is a 4-byte value capable of addressing at most 4 gigabytes. If your application supports HUGE files (greater than 4 gigabytes), you must use the ctSETHGH() and ctGETHGH() functions to set or get the high-order 4 bytes of the file offset. See also Record Offsets Under Huge File Support.
See also
GetGTEKey(), GetKey(), GetLTEKey(), GetLTKey()
