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.\"     @(#)intro.3	8.1 (Berkeley) 6/5/93
.\"
.Dd April 14, 2021
.Dt INTRO 3
.Os
.Sh NAME
.Nm intro
.Nd introduction to the system libraries
.Sh DESCRIPTION
This section provides an overview of the system libraries, their
functions, error returns and other common definitions and concepts.
Most of these functions are available from the standard 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
.\" A subset of the
.\" .Xr libc functions
.\" are available from Fortran;
.\" they are described separately in
.\" .Xr intro 3f .
.Pp
The various system libraries supplied in
.Nx
(followed by the linker flags) are:
.Bl -tag -width "libc (-lc)"
.It Em libasn1 Pq Fl l Ns Ar asn1
The abstract syntax notation (ASN) library provides routines for the
specification of abstract data types.
.It Em libbz2 Pq Fl l Ns Ar bz2
Block-sorting compressor library providing routines for fast and
efficient compression.
.It Em libc Pq Fl l Ns Ar c
The standard C library.
When using the C compiler
.Xr cc 1 ,
it is not necessary to supply the linker flag
.Fl l Ns Ar c
for these functions.
There are several subsystems included inside
.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 Tn encryption and hash routines
see
.Xr md4 3
and
.Xr md5 3 .
.It storage allocation
see
.Xr mpool 3
and
.Xr malloc 3
.It time functions
see
.Xr time 3
.It signal handling
see
.Xr signal 3
.El
.It Em libcom_err Pq Fl l Ns Ar com_err
The common error description library.
See
.Xr com_err 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 libcrypt Pq Fl l Ns Ar crypt
The crypt library.
See
.Xr crypt 3 .
.It Em libcrypto Pq Fl l Ns Ar crypto
The OpenSSL cryptographic library.
See
.Xr crypto 7 .
.It Em libcurses Pq Fl l Ns Ar curses Fl l Ns Ar terminfo
Terminal independent screen management routines
for two dimensional non-bitmap display terminals.
See
.Xr curses 3 .
.It Em libdes Pq Fl l Ns Ar des
The OpenSSL cryptographic library for the DES algorithms.
See
.Xr des 3 .
.It Em libdm Pq Fl l Ns Ar dm
The device-mapper driver access library used for communication with
kernel driver
.Xr dm 4
and for
.Xr lvm 8
subsystem.
.It Em libedit Pq Fl l Ns Ar edit
The command-line editor or editline library.
The editline library provides generic editing and history functions.
See
.Xr editline 3 .
.It Em libform Pq Fl l Ns Ar form
The curses form library provides a terminal-independent form system
using the curses library.
The form library provides facilities for defining forms on terminals.
See
.Xr forms 3 .
.It Em libgssapi Pq Fl l Ns Ar gssapi
The Generic Security Services (GSS) API library.
This library provides
verification services to applications and usually sits above the
cryptographic libraries.
.It Em libhesiod Pq Fl l Ns Ar hesiod
The Hesiod library.
This library provides routines for performing
lookups of Hesiod information, which is stored as text records in the
Domain Name Service.
See
.Xr hesiod 3 .
.It Em libhdb Pq Fl l Ns Ar hdb
The Heimdal Kerberos 5 authentication/authorisation database access
library.
.It Em libintl Pq Fl l Ns Ar intl
The internationalized message handling library.
See
.Xr gettext 3 .
.It Em libipsec Pq Fl l Ns Ar ipsec
The IPsec policy control library.
See
.Xr ipsec_set_policy 3
and
.Xr ipsec_strerror 3 .
.It Em libkadm5clnt Pq Fl l Ns Ar kadm5clnt
The Kerberos 5 administration client library.
.It Em libkadm5srv Pq Fl l Ns Ar kadm5srv
The Kerberos 5 administration server library.
See
.Xr kadm5_pwcheck 3 .
.It Em libkafs Pq Fl l Ns Ar kafs
The Kerberos IV AFS library.
See
.Xr kafs 3 .
.It Em libkdb Pq Fl l Ns Ar kdb
The Kerberos IV authentication/authorisation database access library.
.It Em libkrb Pq Fl l Ns Ar krb
The Kerberos IV library.
.It Em libkrb5 Pq Fl l Ns Ar krb5
The Kerberos 5 library.
See
.Xr krb5 3 .
.It Em libkstream Pq Fl l Ns Ar kstream
Kerberos IV encrypted stream library.
.It Em libkvm Pq Fl l Ns Ar kvm
Kernel data access library.
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 .
.\" The math library is loaded as needed by the Pascal compiler
.\" .Xr pc 1 ,
.\" but not by the C compiler which requires the
.\" .Fl l Ns Ar m
.\" flag (see
.\" .Xr math 3 ) .
.\" .It Em libmp Pq Fl l Ns Ar mp
.\" .It Em libom
.\" Old math library.
.\" .It Em libplot Pq Fl l Ns Ar plot
.\" Device independent plotting functions (see
.\" .Xr plot 3 ) .
.\" .It Em libplotf77 Pq Fl l Ns Ar plotf77
.\" The device independent plotting functions for fortran (see
.\" .Xr plot 3 ) .
.\" .It Em libresolv Pq Fl l Ns Ar resolv
.\" Routines for network address resolution.
.It Em libmenu Pq Fl l Ns Ar menu
The curses menu library.
See
.Xr menus 3 .
.It Em libnvmm Pq Fl l Ns Ar nvmm
.Nx
Virtualization API.
See
.Xr libnvmm 3 .
.It Em libossaudio Pq Fl l Ns Ar ossaudio
Open Sound System compatibility library.
See
.Xr ossaudio 3 .
.It Em libpanel Pq Fl l Ns Ar panel
The curses panel library.
See
.Xr panel 3 .
.It Em libpcap Pq Fl l Ns Ar pcap
The packet capture library.
See
.Xr pcap 3 .
.It Em libpci Pq Fl l Ns Ar pci
The PCI bus access library.
See
.Xr pci 3 .
.It Em libposix Pq Fl l Ns Ar posix
The POSIX compatibility library provides a compatibility interface for
POSIX functions which differ from the standard BSD interfaces.
See
.Xr chown 2
and
.Xr rename 2 .
.It Em libresolv Pq Fl l Ns Ar resolv
The DNS resolver library.
.It Em librmt Pq Fl l Ns Ar rmt
Remote magnetic tape library.
See
.Xr rmtops 3 .
.It Em libroken Pq Fl l Ns Ar roken
A library containing compatibility functions used by Kerberos.
It implements functionality required by the Kerberos implementation not
implemented in the standard
.Nx
libraries.
.It Em librpcsvc Pq Fl l Ns Ar rpcsvc
The Remote Procedure Call (RPC) services library.
See
.Xr rpc 3 .
.It Em libskey Pq Fl l Ns Ar skey
The S/Key one-time password library.
See
.Xr skey 3 .
.It Em libsl Pq Fl l Ns Ar sl
.It Em libss Pq Fl l Ns Ar ss
.It Em libssl Pq Fl l Ns Ar ssl
The secure sockets layer (SSL) library.
See
.Xr ssl 7 .
.It Em libtelnet Pq Fl l Ns Ar telnet
The telnet library.
.It Em libterminfo Pq Fl l Ns Ar terminfo
The terminal-independent operation library.
See
.Xr terminfo 3 .
.It Em libusbhid Pq Fl l Ns Ar usbhid
The Universal Serial Bus (USB) Human Interface Devices access library.
See
.Xr libusbhid 3 .
.It Em libutil Pq Fl l Ns Ar util
The system utilities library.
See
.Xr util 3 .
.It Em libwrap Pq Fl l Ns Ar wrap
The TCP wrappers library.
See
.Xr hosts_access 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
General-purpose compression library.
See
.Xr zlib 3 .
.El
.Sh SEE ALSO
.Xr cc 1 ,
.Xr ld 1 ,
.Xr nm 1 ,
.Xr rtld 1 ,
.Xr intro 2
.Sh HISTORY
An
.Nm
manual appeared in
.At v7 .