qfits is a stand-alone library written in C to interact with files
complying with the FITS format. It is fast and portable over any kind
of POSIX-compliant platform.
Rather than going through the FITS format specification and trying to
implement some support for everything that is described there, this
library was built day after day upon request. This guarantees that
all the functions you will find in the library have been written for
some purpose in the VLT pipeline context, and all of them are used
daily in a production environment.