1.\" Copyright (c) 1980, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)intro.3 8.1 (Berkeley) 6/5/93 29.\" $FreeBSD$ 30.\" 31.Dd March 22, 2017 32.Dt INTRO 3 33.Os 34.Sh NAME 35.Nm intro 36.Nd introduction to the C libraries 37.Sh DESCRIPTION 38This section provides an overview of the C 39library functions, their error returns and other 40common definitions and concepts. 41Most of these functions are available from the C library, 42.Em libc . 43Other libraries, such as the math library, 44.Em libm , 45must be indicated at compile time with the 46.Fl l 47option of the compiler. 48.Pp 49The various libraries (followed by the loader flag): 50.Bl -tag -width "libc (-lc)" 51.It Em libc Pq Fl l Ns Ar c 52Standard C library functions. 53When using the C compiler 54.Xr cc 1 , 55it is not necessary 56to supply the loader flag 57.Fl l Ns Ar c 58for these functions. 59There are several `libraries' or groups of functions included inside of 60.Em libc 61: the standard 62.Tn I/O 63routines, 64database routines, 65bit operators, 66string operators, 67character tests and character operators, 68des encryption routines, 69storage allocation, time functions, signal handling and more. 70.It Em libcurses Pq Fl l Ns Ar curses Fl l Ns Ar termcap 71Terminal independent screen management routines 72for two dimensional non-bitmap display terminals. 73(See 74.Xr ncurses 3 . ) 75.It Em libcompat Pq Fl l Ns Ar compat 76Functions which are obsolete but are available for compatibility with 77.Bx 4.3 . 78In particular, 79a number of system call interfaces provided in previous releases of 80.Bx 81have been included for source code compatibility. 82Use of these routines should, for the most part, be avoided. 83The manual page entry for each compatibility routine 84indicates the proper interface to use. 85.It Em libkvm Pq Fl l Ns Ar kvm 86Functions used to access kernel memory are in this library. 87They can be used 88against both a running system and a crash dump. 89(See 90.Xr kvm 3 . ) 91.It Em libl Pq Fl l Ns Ar l 92The library for 93.Xr lex 1 . 94.It Em libm Pq Fl l Ns Ar m 95The math library, 96.Em libm . 97The math library is loaded as needed by the Pascal compiler, 98but not by the C compiler which requires the 99.Fl l Ns Ar m 100flag. 101(See 102.Xr math 3 . ) 103.It Em libmp Pq Fl l Ns Ar mp 104.It Em libtermcap Pq Fl l Ns Ar termcap 105The terminal independent operation library package. 106(See 107.Xr termcap 3 . ) 108.It Em liby Pq Fl l Ns Ar y 109The library for 110.Xr yacc 1 . 111.El 112.Sh FILES 113.Bl -tag -width /usr/lib/libm_p.a -compact 114.It Pa /usr/lib/libc.a 115the C library 116.It Pa /usr/lib/libc_p.a 117the C library compiled for profiling 118.It Pa /usr/lib/libm.a 119the math library 120.It Pa /usr/lib/libm_p.a 121the math library compiled for profiling 122.El 123.Sh SEE ALSO 124.Xr cc 1 , 125.Xr ld 1 , 126.Xr nm 1 , 127.Xr intro 2 , 128.Xr math 3 , 129.Xr stdio 3 130.Sh HISTORY 131An 132.Nm 133manual appeared in 134.At v7 . 135