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.\"     @(#)intro.3	8.1 (Berkeley) 6/5/93
.\" $FreeBSD$
.\"
.Dd October 6, 2020
.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 (-lbluetooth)"
.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 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 .