Usually the functions defined in standard, specialized, or user-defined libraries are declared (their prototypes are given) in header files. The appropriate header should be #included into any source file accessing these functions*.
(In truth, the user may provide the appropriate function prototypes himself/herself instead of #including the standard header file. This, however, is a very poor practice since future versions of the compiler may change the function implementation slightly causing the user's prototype to be inaccurate. Portability is also jeapordized. Also note that some functions are implemented as macros in the standard header file.)
This chapter describes only a sampling of frequently-used functions from the standard C function libraries. A C reference text or manual should be consulted for greater breadth and detail.
Consult the documentation for your own compiler to see what specialized libraries are available, if portability is not crucial.
Appendix 1 describes using libraries with TC projects.
