INTRO(3)                                                 INTRO(3)

     NAME
          intro - introduction to library functions

     SYNOPSIS
          #include <stdio.h>

          #include <math.h>

     DESCRIPTION
          This section describes functions that may be found in vari-
          ous libraries, other than those functions that directly
          invoke UNIX system primitives, which are described in sec-
          tion 2.  Functions are divided into various libraries dis-
          tinguished by the section number at the top of the page:

          (3)   These functions, together with those of section 2 and
                those marked (3S) and (3M), constitute library libc,
                which is automatically loaded by the C compiler cc(1)
                and the Fortran compiler f77(1). The link editor ld(1)
                searches this library under option -lc . Declarations
                for some of these functions may be obtained from
                include files indicated on the appropriate pages.

          (3F)  These functions are in the Fortran library, libF77,
                automatically loaded by the Fortran compiler, and
                searched under option -lF77 of the link editor.

          (3M)  These functions constitute the math library, part of
                libc. (On other systems they must be loaded by -lm).
                Declarations for these functions may be obtained from
                the include file <math.h>.

          (3S)  These functions constitute the `standard IO package',
                see stdio(3), part of libc already mentioned.  Decla-
                rations for these functions may be obtained from the
                include file <stdio.h>.

          (3X)  Various specialized libraries have not been given dis-
                tinctive captions.  Files in which such libraries are
                found are named on appropriate pages.

     FILES
          /lib/libc.a

     SEE ALSO
          stdio(3), nm(1), ld(1), cc(1), f77(1), intro(2)

     DIAGNOSTICS
          Functions in the math library (3M) may return conventional
          values when the function is undefined for the given

     INTRO(3)                                                 INTRO(3)

          arguments or when the value is not representable.  In these
          cases the external variable errno (see intro(2)) is set to
          the value EDOM or ERANGE, defined in the include file
          <math.h>.