v7 man page for intro

INTRO(3)						     Library Functions Manual							  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 various libraries, other than those functions that directly invoke UNIX system primi-
       tives, which are described in section 2.  Functions are divided into various libraries distinguished by the section number at  the  top	of
       the page:

       (3)   These  functions,	together  with those of section 2 and those marked (3S), 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 the `-lc' option.   Declara-
	     tions for some of these functions may be obtained from include files indicated on the appropriate pages.

       (3M)  These functions constitute the math library, libm.  They are automatically loaded as needed by the Fortran compiler f77(1).  The link
	     editor searches this library under the `-lm' option.  Declarations for  these  functions  may  be	obtained  from	the  include  file
	     <math.h>.

       (3S)  These  functions  constitute  the	`standard  I/O package', see stdio(3).	These functions are in the library libc already mentioned.
	     Declarations for these functions may be obtained from the include file <stdio.h>.

       (3X)  Various specialized libraries have not been given distinctive captions.  The files in which these libraries are found  are  named	on
	     the appropriate pages.

FILES
       /lib/libc.a
       /lib/libm.a, /usr/lib/libm.a (one or the other)

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 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.  The  values  of  EDOM
       and ERANGE are defined in the include file <math.h>.

ASSEMBLER
       In assembly language these functions may be accessed by simulating the C calling sequence.  For example, ecvt(3) might be called this way:

	      setd
	      mov  $sign,-(sp)
	      mov  $decpt,-(sp)
	      mov  ndigit,-(sp)
	      movf value,-(sp)
	      jsr  pc,_ecvt
	      add  $14.,sp

																	  INTRO(3)