reading configuration files

I need the most efficient(performance/speed wise) to read configuration from a file in c under linux. I have not decided on the config format yet, but I would prefer(I'm all ears for better formats) the following format: buttons 3 size 100 ...etc.(the option name then the option value delimited by whitespace) how can I read the options, should I go for strcmp? or should I go for character by character manual comparison? is there a more efficient option? I want the program to: - be as quick as possible(time) - use as little cpu time as possible - use as little memory as possible

this code will be written for linux(generic) so far I'm using: xtest,stdio,stdlib, string libraries

I would rather code everything myself than use external libraries(libraries not part of most linux distributions

thanks