Is there a well-known general purpose library for standard C. I am thinking of something like Boost for C ++.
I found the POSIX C library ... any other?
GLib , GObject, and GTK + (Wikipedia links) are good places to start. ( GLib , GObject, and GTK are part of GTK + Project ).
For numerical functions and algebra, there are the GNU Science Library , as well as implementations of CLAPACK and CBLAS (GSL includes CBLAS).
See also List of Wikipedia Numerical Libraries . If you find more, consider contributing to the Wiki.
I used GLib , which provides almost all the functionality of standard c libs.