I am writing a file in binary using fwrite. I am opening this file for read and write. After each write, the file pointer points to the end of the file, and I need to be able to read backwards x number of bytes.
I could move the pointer backwards X bytes, and then do a forward read (I would prefer this way), but I'm not sure how to do this either.
Any suggestions?
Look into fseek. It has a way to reference from the beginning of the file, the end of the file or the current position. One of the latter two methods should work for you.
Check out fseek(3): reposition stream - Linux man page. Example: fseek(fp, sizeof(record), SEEK_CUR);
If you understand what you're doing, you're not learning anything.
fseek seems to be exactly what I'm looking for! Thanks so much, again!!
With fseek, there's no way to go backwards from the end is there?
For example, the current pointer is at the end, and I know I need the last 4 bytes back. Can i just go back 4 bytes?
It seems that I have to start from the very start and go forward total_bytes - 4bytes?
maybe I have to a combination of fgetpos and fsetpos
If forward is positive, what would backwards be?
Some times, I'm smart. Others, the -1 of smart.
It works. Thanks you lol.
Read the docs... There are in fact three options for seeking in a file... SEEK_SET relative to the beginning of the file, SEEK_CUR relative to the current position and SEEK_END relative to the end of the file...Originally Posted by dayalsoap
Reading is good....
