Reg. fseek
Hi Folks,
I have a file with some records in it. As I process the records one by one I need to move the pointer to the beginning of the next record (next line). How do I implement this??? I used fseek but I couldn't implement it..
The records in the file are not of constant length. Please help me out. thanks in advance.
Pokks.
If the size of the records is not known in advance, the only way to do it is by starting at the beginning and reading one line at a time until you reach the line you're interested in. If you use newline termination on each record and your records are text, not binary, fgets() should work nicely for this.
If this is something you do repeatedly, you can use ftell() before reading each line and build an index containing the line identifier (line #, key value, and/or some other such data) and the offset (from ftell()), and use the offset in calls to fseek() to position the file before a call to fgets() to read the record. (This a way to implement a simple ISAM text database, BTW.)
If you're updating these records, keep in mind that you should not change the length of any record during the in-place update.
Insert obnoxious but pithy remark here
