Buffered reading from stdin using fread in C

Question

I am trying to efficiently read from the stdin by using setvbuf in `_IOFBF~ mode. I am new to buffering. I am looking for working examples

Answer 1

The reason all this permature optimisation has a negligable effect on the runtime is that in *nix and windows type operating systems the OS handles all I/O to and from the file system and implements 30 years worth of research, trickery and deviousness to do this very efficiently.

The buffering you are trying to control is merely the block of memory used by your program. So any increases in speed will be minimal (the effect of doing 1 large 'mov' verses 6 or 7 smaller 'mov' instructions).

If you really want to speed this up try "mmap" which allows you direct access the data in the file systems buffer.