.\" Copyright (c) 1980, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)intro.3	8.1 (Berkeley) 6/5/93
.\"
.Dd November 7, 2022
.Dt INTRO 3
.Os
.Sh NAME
.Nm intro
.Nd introduction to the C libraries
.Sh SYNOPSIS
.Nm cc
.Op Ar flags
.Ar
.Op Fl llibrary
.Sh DESCRIPTION
This section provides an overview of the C
library functions, their error returns and other
common definitions and concepts.
Most of these functions are available from the C library,
.Em libc .
Other libraries, such as the math library,
.Em libm ,
must be indicated at compile time with the
.Fl l
option of the compiler.
.Pp
The various libraries (followed by the loader flag):
.Bl -tag -width "libbluetooth"
.It Em libbluetooth
.Pq Fl l Ns Ar bluetooth
The bluetooth library.
See
.Xr bluetooth 3 .
.It Em libc
.Pq Fl l Ns Ar c
Standard C library functions.
When using the C compiler
.Xr cc 1 ,
it is not necessary
to supply the loader flag
.Fl l Ns Ar c
for these functions.
There are several `libraries' or groups of functions included inside of
.Em libc :
.Bl -tag -width "XXXXXX"
.It standard I/O routines
see
.Xr stdio 3
.It database routines
see
.Xr db 3
.It bit operators
see
.Xr bitstring 3
.It string operators
see
.Xr string 3
.It character tests and character operators
.It storage allocation
see
.Xr mpool 3
.It regular-expressions
see
.Xr regex 3
.It remote procedure calls (RPC)
see
.Xr rpc 3
.It time functions
see
.Xr time 3
.It signal handling
see
.Xr signal 3
.El
.It Em libcalendar
.Pq Fl l Ns Ar calendar
The calendar arithmetic library.
See
.Xr calendar 3 .
.It Em libcam
.Pq Fl l Ns Ar cam
The common access method user library.
See
.Xr cam 3 .
.It Em libcrypt
.Pq Fl l Ns Ar crypt
The crypt library.
See
.Xr crypt 3 .
.It Em libcurses
.Pq Fl l Ns Ar curses Fl l Ns Ar termcap
Terminal independent screen management routines
for two dimensional non-bitmap display terminals.
See
.Xr ncurses 3 .
.It Em libcuse
.Pq Fl l Ns Ar cuse
The userland character device library.
See
.Xr cuse 3 .
.It Em libcompat
.Pq Fl l Ns Ar compat
Functions which are obsolete but are available for compatibility with
.Bx 4.3 .
In particular,
a number of system call interfaces provided in previous releases of
.Bx
have been included for source code compatibility.
Use of these routines should, for the most part, be avoided.
The manual page entry for each compatibility routine
indicates the proper interface to use.
.It Em libdevinfo
.Pq Fl l Ns Ar devinfo
The Device and Resource Information Utility library.
See
.Xr devinfo 3 .
.It Em libdevstat
.Pq Fl l Ns Ar devstat
The Device Statistics library.
See
.Xr devstat 3 .
.It Em libdwarf
.Pq Fl l Ns Ar dwarf
The DWARF access library.
See
.Xr dwarf 3 .
.It Em libelf
.Pq Fl l Ns Ar elf
The ELF access library.
See
.Xr elf 3 .
.It Em libfetch
.Pq Fl l Ns Ar fetch
The file transfer library.
See
.Xr fetch 3 .
.It Em libfigpar
.Pq Fl l Ns Ar figpar
The configuration file parsing library.
See
.Xr figpar 3 .
.It Em libgpio
.Pq Fl l Ns Ar gpio
The general-purpose input output library (GPIO).
See
.Xr gpio 3 .
.It Em libgssapi
.Pq Fl l Ns Ar gssapi
The generic security service application programming
interface.
See
.Xr gssapi 3 .
.It Em libjail
.Pq Fl l Ns Ar jail
The jail library.
See
.Xr jail 3 .
.It Em libkvm
.Pq Fl l Ns Ar kvm
Functions used to access kernel memory are in this library.
They can be used
against both a running system and a crash dump.
See
.Xr kvm 3 .
.It Em libl
.Pq Fl l Ns Ar l
The library for
.Xr lex 1 .
.It Em libm
.Pq Fl l Ns Ar m
The math library.
See
.Xr math 3 .
.It Em libmd
.Pq Fl l Ns Ar md
The message digest library.
See
.Xr md4 3 ,
.Xr md5 3 ,
.Xr sha 3 ,
.Xr sha256 3 ,
.Xr sha512 3 ,
.Xr ripemd 3 ,
.Xr skein 3 .
.It Em libmp
.Pq Fl l Ns Ar mp
.It Em libpam
.Pq Fl l Ns Ar pam
The pluggable authentication module library.
See
.Xr pam 3 .
.It Em libpcap
.Pq Fl l Ns Ar pcap
The packet capture library.
See
.Xr pcap 3 .
.It Em libpmc
.Pq Fl l Ns Ar pmc
The performance counters library.
See
.Xr pmc 3 .
.It Em libpthread
.Pq Fl l Ns Ar pthread
The POSIX threads library.
See
.Xr pthread 3 .
.It Em libstdthreads
.Pq Fl l Ns Ar stdthreads
The ISO C11 standard
.In threads.h
library.
See
.Xr thrd_create 3 .
.It Em libsysdecode
.Pq Fl l Ns Ar sysdecode
The system argument decoding library.
See
.Xr sysdecode 3 .
.It Em libtermcap
.Pq Fl l Ns Ar termcap
The terminal independent operation library package.
See
.Xr termcap 3 .
.It Em libusb
.Pq Fl l Ns Ar usb
The USB access library.
See
.Xr usb 3 .
.It Em libvgl
.Pq Fl l Ns Ar vgl
The video graphics library.
See
.Xr vgl 3 .
.It Em liby
.Pq Fl l Ns Ar y
The library for
.Xr yacc 1 .
.It Em libz
.Pq Fl l Ns Ar z
The general-purpose data compression library.
See
.Xr zlib 3 .
.El
.Sh FILES
.Bl -tag -width /usr/lib/libm_p.a -compact
.It Pa /usr/lib/libc.a
the C library
.It Pa /usr/lib/libc_p.a
the C library compiled for profiling
.It Pa /usr/lib/libm.a
the math library
.It Pa /usr/lib/libm_p.a
the math library compiled for profiling
.El
.Sh SEE ALSO
.Xr cc 1 ,
.Xr ld 1 ,
.Xr nm 1 ,
.Xr intro 2 ,
.Xr math 3 ,
.Xr stdio 3
.Sh HISTORY
An
.Nm
manual appeared in
.At v7 .