intro(3) [redhat man page]

INTRO(3)						     Linux Programmer's Manual							  INTRO(3)

NAME

       intro - Introduction to library functions

DESCRIPTION

       This  chapter  describes all library functions excluding the library functions described in chapter 2, which implement system calls.  There
       are various function groups which can be identified by a letter which is appended to the chapter number:

       (3C)   These functions, the functions from chapter 2 and from chapter 3S are contained in the C standard library libc, which will  be  used
	      by cc(1) by default.

       (3S)   These functions are parts of the stdio(3) library.  They are contained in the standard C library libc.

       (3M)   These  functions	are contained in the arithmetic library libm.  They are used by the f77(1) FORTRAN compiler by default, but not by
	      the cc(1) C compiler, which needs the option -lm.

       (3F)   These functions are part of the FORTRAN library libF77.  There are no special compiler flags needed to use these functions.

       (3X)   Various special libraries.  The manual pages documenting their functions specify the library names.

AUTHORS

       Look at the header of the manual page for the author(s) and copyright conditions.  Note that these can be different from page to page!

Linux								    1995-12-13								  INTRO(3)

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)