xref: /illumos-gate/usr/src/man/man3/Intro.3 (revision ddb365bfc9e868ad24ccdcb0dc91af18b10df082) 
 te
 Copyright 2019 Peter Tribble
 Copyright 2015 Joyent, Inc.
 Copyright (c) 2009, Sun Microsystems, Inc. All Rights Reserved.
 The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License. You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.
 See the License for the specific language governing permissions and limitations under the License. When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this CDDL HEADER, with
 the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
 INTRO 3 "Sep 12, 2021"
 NAME
Intro, intro - introduction to functions and libraries

 DESCRIPTION
This section describes functions found in various Solaris libraries, other than
those functions described in Section 2 of this manual that directly invoke UNIX
system primitives. Function declarations can be obtained from the
#include files indicated on each page. Pages are grouped by library and
are identified by the library name (or an abbreviation of the library name)
after the section number. Collections of related libraries are grouped into
volumes as described below. The first volume contains pages describing the
contents of each shared library and each header used by the functions, macros,
and external variables described in the remaining volumes.

 "Library Interfaces and Headers"
This volume describes the contents of each shared library and each header used
by functions, macros, and external variables described in the remaining
volumes.
(3LIB)


The libraries described in this section are implemented as shared objects.
Descriptions of shared objects can include a definition of the global symbols
that define the shared objects' public interface, for example SUNW_1.1.
Other interfaces can exist within the shared object, for example
SUNWprivate.1.1. The public interface provides a stable, committed set of
symbols for application development. The private interfaces are for internal
use only, and could change at any time.



(3HEAD)


The headers described in this section are used by functions, macros, and
external variables. Headers contain function prototypes, definitions of
symbolic constants, common structures, preprocessor macros, and defined types.
Each function described in the remaining five volumes specifies the headers
that an application must include in order to use that function. In most cases
only one header is required. These headers are present on an application
development system; they do have to be present on the target execution system.




 "Basic Library Functions"
The functions described in this volume are the core C library functions that
are basic to application development.
(3C)


These functions, together with those of Section 2, constitute the standard C
library, libc, which is automatically linked by the C compilation system.
The standard C library is implemented as a shared object, libc.so. See
libc(3LIB) and the "C Compilation System" chapter of the ANSI C
Programmer's Guide for a discussion. Some functions behave differently in
standard-conforming environments. This behavior is noted on the individual
manual pages. See standards(7).
The libpthread and libthread libraries are filter libraries on
libc that are used for building multithreaded applications:
libpthread implements the POSIX (see standards(7)) threads
interface, whereas libthread implements the Solaris threads interface.
See MULTITHREADED APPLICATIONS, below.



(3C_DB)


These functions constitute the threads debugging library, libc_db. This
library is implemented as a shared object, libc_db.so, but is not
automatically linked by the C compilation system. Specify -lc_db on the
cc command line to link with this library. See libc_db(3LIB).



(3MALLOC)


These functions constitute the various memory allocation libraries:
libmalloc, libbsdmalloc, libmapmalloc, libmtmalloc, and
libumem. Each of these libraries is implemented as a shared object
(libmalloc.so, libbsdmalloc.so, libmapmalloc.so,
libmtmalloc.so, and libumem.so). These libraries are not
automatically linked by the C compilation system. Specify -lmalloc,
-lbsdmalloc, -lmapmalloc, -lmtmalloc, and -lumem to
link with, respectively, libmalloc, libbsdmalloc,
libmapmalloc, libmtmalloc, and libumem. See
libmalloc(3LIB), libbsdmalloc(3LIB), libmapmalloc(3LIB),
libmtmalloc(3LIB), and libumem(3LIB).




 "Networking Library Functions"
The functions described in this volume comprise the various networking
libraries.
(3COMMPUTIL)


These functions constitute the communication protocol parser utilities library,
libcommputil. This library is implemented as a shared object,
libcommputil.so, but it is not automatically linked by the C compilation
system. Specify -lcommputil on the cc command line to link with
this library. See libcommputil(3LIB).



(3DLPI)


These functions constitute the data link provider interface library,
libdlpi. This library is implemented as a shared object,
libdlpi.so, but it is not automatically linked by the C compilation
system. Specify -ldlpi on the cc command line to link with this
library. See libdlpi(3LIB).



(3DNS_SD)


These functions constitute the DNS service discovery library, libdns_sd.
This library is implemented as a shared object, libdns_sd.so, but it is
not automatically linked by the C compilation system. Specify -ldns_sd on
the cc command line to link with this library. See libdns_sd(3LIB).



(3GSS)


These functions constitute the generic security services library. This library
is implemented as a shared object, libgss.so, but it is not automatically
linked by the C compilation system. Specify -lgss on the cc command
line to link with this library. See libgss(3LIB).



(3LDAP)


These functions constitute the lightweight directory access protocol library,
libldap. This library is implemented as a shared object,
libldap.so, but is not automatically linked by the C compilation system.
Specify -lldap on the cc command line to link with this library.
See ldap(3LDAP).



(3NSL)


These functions constitute the network service library, libnsl. This
library is implemented as a shared object, libnsl.so, but is not
automatically linked by the C compilation system. Specify -lnsl on the
cc command line to link with this library. See libnsl(3LIB).
Many base networking functions are also available in the X/Open networking
interfaces library, libxnet. See section (3XNET) below for more
information on the libxnet interfaces.



(3RESOLV)


These functions constitute the resolver library, libresolv. This library
is implemented as a shared object, libresolv.so, but is not automatically
linked by the C compilation system. Specify -lresolv on the cc
command line to link with this library. See libresolv(3LIB).



(3RPC)


These functions constitute the remote procedure call libraries, librpcsvc
and librpcsoc. The latter is provided for compatibility only; new
applications should not link to it. Both libraries are implemented as shared
objects, librpcsvc.so and librpcsoc.so, respectively. Neither
library is automatically linked by the C compilation system. Specify
-lrpcsvc or -lrpcsoc on the cc command line to link with
these libraries. See librpcsvc(3LIB).



(3SASL)


These functions constitute the simple authentication and security layer
library, libsasl. This library is implemented as a shared object,
libsasl.so, but it is not automatically linked by the C compilation
system. Specify -lsasl on the cc command line to link with this
library. See libsasl(3LIB).



(3SIP)


These functions constitute the session initiation protocol library,
libsip. This library is implemented as a shared object, libsip.so,
but it is not automatically linked by the C compilation system. Specify
-lsip on the cc command line to link with this library. See
libsip(3LIB).



(3SLP)


These functions constitute the service location protocol library, libslp.
This library is implemented as a shared object, libslp.so, but it is not
automatically linked by the C compilation system. Specify -lslp on the
cc command line to link with this library. See libslp(3LIB).



(3SOCKET)


These functions constitute the sockets library, libsocket. This library
is implemented as a shared object, libsocket.so, but is not automatically
linked by the C compilation system. Specify -lsocket on the cc
command line to link with this library. See libsocket(3LIB).



(3XNET)


These functions constitute X/Open networking interfaces which comply with the
X/Open CAE Specification, Networking Services, Issue 4 (September, 1994). This
library is implemented as a shared object, libxnet.so, but is not
automatically linked by the C compilation system. Specify -lxnet on the
cc command line to link with this library. See libxnet(3LIB) and
standards(7) for compilation information.





Under all circumstances, the use of the Sockets API is recommended over the XTI
and TLI APIs. If portability to other XPGV4v2 (see standards(7)) systems
is a requirement, the application must use the libxnet interfaces. If
portability is not required, the sockets interfaces in libsocket and
libnsl are recommended over those in libxnet. Between the XTI and
TLI APIs, the XTI interfaces (available with libxnet) are
recommended over the TLI interfaces (available with libnsl).

 "Curses Library Functions"
The functions described in this volume comprise the libraries that provide
graphics and character screen updating capabilities.
(3CURSES)


The functions constitute the following libraries:
libcurses


These functions constitute the curses library, libcurses. This library is
implemented as a shared object, libcurses.so, but is not automatically
linked by the C compilation system. Specify -lcurses on the cc
command line to link with this library. See libcurses(3LIB).



libform


These functions constitute the forms library, libform. This library is
implemented as a shared object, libform.so, but is not automatically
linked by the C compilation system. Specify -lform on the cc
command line to link with this library. See libform(3LIB).



libmenu


These functions constitute the menus library, libmenu. This library is
implemented as a shared object, libmenu.so, but is not automatically
linked by the C compilation system. Specify -lmenu on the cc
command line to link with this library. See libmenu(3LIB).



libpanel


These functions constitute the panels library, libpanel. This library is
implemented as a shared object, libpanel.so, but is not automatically
linked by the C compilation system. Specify -lpanel on the cc
command line to link with this library. See libpanel(3LIB).






(3XCURSES)


These functions constitute the X/Open curses library, located in
/usr/xpg4/lib/libcurses.so. This library provides a set of
internationalized functions and macros for creating and modifying input and
output to a terminal screen. Included in this library are functions for
creating windows, highlighting text, writing to the screen, reading from user
input, and moving the cursor. X/Open Curses is designed to optimize screen
update activities. The X/Open Curses library conforms fully with Issue 4 of the
X/Open Extended Curses specification. See libcurses(3XCURSES).




 "Extended Library Functions"
The functions described in this volume comprise the following specialized
libraries:
(3BSM)


These functions constitute the auditing library, libbsm. This
library is implemented as a shared object, libbsm.so, but is not
automatically linked by the C compilation system. Specify -lbsm on the
cc command line to link with this library. See libbsm(3LIB).



(3CFGADM)


These functions constitute the configuration administration library,
libcfgadm. This library is implemented as a shared object,
libcfgadm.so, but is not automatically linked by the C compilation
system. Specify -lcfgadm on the cc command line to link with this
library. See libcfgadm(3LIB).



(3CONTRACT)


These functions constitute the contract management library, libcontract.
This library is implemented as a shared object, libcontract.so, but is
not automatically linked by the C compilation system. Specify -lcontract
on the cc command line to link with this library. See
libcontract(3LIB).



(3CPC)


These functions constitute the CPU performance counter library, libcpc,
and the process context library, libpctx. These libraries are implemented
as shared objects, libcpc.so and libpctx.so, respectively, but are
not automatically linked by the C compilation system. Specify -lcpc or
-lpctx on the cc command line to link with these libraries. See
libcpc(3LIB) and libpctx(3LIB).



(3DAT)


These functions constitute the direct access transport library, libdat.
This library is implemented as a shared object, libdat.so, but is not
automatically linked by the C compilation system. Specify -ldat on the
cc command line to link with this library. See libdat(3LIB).



(3DEVID)


These functions constitute the device ID library, libdevid. This
library is implemented as a shared object, libdevid.so, but is not
automatically linked by the C compilation system. Specify -ldevid on the
cc command line to link with this library. See libdevid(3LIB).



(3DEVINFO)


These functions constitute the device information library, libdevinfo.
This library is implemented as a shared object, libdevinfo.so, but is not
automatically linked by the C compilation system. Specify -ldevinfo on
the cc command line to link with this library. See
libdevinfo(3LIB).



(3ELF)


These functions constitute the ELF access library, libelf, (Extensible
Linking Format). This library provides the interface for the creation and
analyses of "elf" files; executables, objects, and shared objects. libelf
is implemented as a shared object, libelf.so, but is not automatically
linked by the C compilation system. Specify -lelf on the cc command
line to link with this library. See libelf(3LIB).



(3EXACCT)


These functions constitute the extended accounting access library,
libexacct, and the project database access library, libproject.
These libraries are implemented as shared objects, libexacct.so and
libproject.so, respectively, but are not automatically linked by the C
compilation system. Specify -lexacct or -lproject on the cc
command line to link with these libraries. See libexacct(3LIB) and
libproject(3LIB).



(3FCOE)


These functions constitute the Fibre Channel over Ethernet port management
library. This library is implemented as a shared object, libfcoe.so, but
is not automatically linked by the C compilation system. Specify -lfcoe
on the cc command line to link with this library. See
libfcoe(3LIB).



(3FSTYP)


These functions constitute the file system type identification library. This
library is implemented as a shared object, libfstyp.so, but is not
automatically linked by the C compilation system. Specify -lfstyp on the
cc command line to link with this library. See libfstyp(3LIB).



(3GEN)


These functions constitute the string pattern-matching and pathname
manipulation library, libgen. This library is implemented as a shared
object, libgen.so, but is not automatically linked by the C compilation
system. Specify -lgen on the cc command line to link with this
library. See libgen(3LIB).



(3HBAAPI)


These functions constitute the common fibre channel HBA information library,
libhbaapi. This library is implemented as a shared object,
libhbaapi.so, but is not automatically linked by the C compilation
system. Specify -lhbaapi on the cc command line to link with this
library. See libhbaapi(3LIB).



(3ISCSIT)


These functions constitute the iSCSI Management library, libiscsit. This
library is implemented as a shared object, libiscsit.so, but is not
automatically linked by the C compilation system. Specify -liscsit on the
cc command line to link with this library. See libiscsit(3LIB).



(3KSTAT)


These functions constitute the kernel statistics library, which is implemented
as a shared object, libkstat.so, but is not automatically linked by the C
compilation system. Specify -lkstat on the cc command line to link
with this library. See libkstat(3LIB).



(3KVM)


These functions allow access to the kernel's virtual memory library, which is
implemented as a shared object, libkvm.so, but is not automatically
linked by the C compilation system. Specify -lkvm on the cc command
line to link with this library. See libkvm(3LIB).



(3LGRP)


These functions constitute the locality group library, which is implemented as
a shared object, liblgrp.so, but is not automatically linked by the C
compilation system. Specify -llgrp on the cc command line to link
with this library. See liblgrp(3LIB).



(3M)


These functions constitute the mathematical library, libm. This library
is implemented as a shared object, libm.so, but is not automatically
linked by the C compilation system. Specify -lm on the cc command
line to link with this library. See libm(3LIB).



(3MAIL)


These functions constitute the user mailbox management library, libmail.
This library is implemented as a shared object, libmail.so, but is not
automatically linked by the C compilation system. Specify -lmail on the
cc command line to link with this library. See libmail(3LIB).



(3MP)


These functions constitute the integer mathematical library, libmp. This
library is implemented as a shared object, libmp.so, but is not
automatically linked by the C compilation system. Specify -lmp on the
cc command line to link with this library. See libmp(3LIB).



(3MPAPI)


These functions constitute the Common Multipath Management library,
libMPAPI. This library is implemented as a shared object,
libMPAPI.so, but is not automatically linked by the C compilation system.
Specify -lMPAPI on the cc command line to link with this library.
See libMPAPI(3LIB).



(3MVEC)


These functions constitute the vector mathematical library, libmvec. This
library is implemented as a shared object, libmvec.so, but is not
automatically linked by the C compilation system. Specify -lmvec on the
cc command line to link with this library. See libmvec(3LIB).



(3NVPAIR)


These functions constitute the name-value pair library, libnvpair. This
library is implemented as a shared object, libnvpair.so, but is not
automatically linked by the C compilation system. Specify -lnvpair on the
cc command line to link with this library. See libnvpair(3LIB).



(3PAM)


These functions constitute the pluggable authentication module library,
libpam. This library is implemented as a shared object, libpam.so,
but is not automatically linked by the C compilation system. Specify
-lpam on the cc command line to link with this library. See
libpam(3LIB).



(3PAPI)


These functions constitute the Free Standards Group Open Printing API (PAPI)
library, libpapi. This library is implemented as a shared object,
libpapi.so, but is not automatically linked by the C compilation system.
Specify -lpapi on the cc command line to link with this library.
See libpapi(3LIB).



(3PICL)


These functions constitute the PICL library, libpicl. This library is
implemented as a shared object, libpicl.so, but is not automatically
linked by the C compilation system. Specify -lpicl on the cc
command line to link with this library. See libpicl(3LIB) and
libpicl(3PICL).



(3PICLTREE)


These functions constitute the PICL plug-in library, libpicltree. This
library is implemented as a shared object, libpicltree.so, but is not
automatically linked by the C compilation system. Specify -lpicltree on
the cc command line to link with this library. See
libpicltree(3LIB) and libpicltree(3PICLTREE).



(3POOL)


These functions constitute the pool configuration manipulation library,
libpool. This library is implemented as a shared object,
libpool.so, but is not automatically linked by the C compilation system.
Specify -lpool on the cc command line to link with this library.
See libpool(3LIB).



(3PROC)


These functions constitute the process manipulation library,
libproc. This library is implemented as a shared object,
libproc.so, but it is not automatically linked by the C compilation
system. Specify -lproc on the cc command line to link with this
library. See libproc(3LIB).



(3PROJECT)


These functions constitute the project database access library,
libproject. This library is implemented as a shared object,
libproject.so, but is not automatically linked by the C compilation
system. Specify -lproject on the cc command line to link with this
library. See libproject(3LIB).



(3RSM)


These functions constitute the remote shared memory library, librsm. This
library is implemented as a shared object, librsm.so, but is not
automatically linked by the C compilation system. Specify -lrsm on the
cc command line to link with this library. See librsm(3LIB).



(3SCF)


These functions constitute the service configuration facility library,
libscf. This library is implemented as a shared object, libscf.so,
but is not automatically linked by the C compilation system. Specify
-lscf on the cc command line to link with this library. See
libscf(3LIB).



(3SEC)


These functions constitute the file access control library, libsec. This
library is implemented as a shared object, libsec.so, but is not
automatically linked by the C compilation system. Specify -lsec on the
cc command line to link with this library. See libsec(3LIB).



(3SECDB)


These functions constitute the security attributes database library,
libsecdb. This library is implemented as a shared object,
libsecdb.so, but is not automatically linked by the C compilation system.
Specify -lsecdb on the cc command line to link with this library.
See libsecdb(3LIB).



(3STMF)


These functions constitute the SCSI Target Mode Framework library,
libstmf. This library is implemented as a shared object,
libstmf.so, but is not automatically linked by the C compilation system.
Specify -lstmf on the cc command line to link with this library.
See libstmf(3LIB).



(3SYSEVENT)


These functions constitute the system event library, libsysevent. This
library is implemented as a shared object, libsysevent.so, but is not
automatically linked by the C compilation system. Specify -lsysevent on
the cc command line to link with this library. See
libsysevent(3LIB).



(3TECLA)


These functions constitute the interactive command-line input library,
libtecla. This library is implemented as a shared object,
libtecla.so, but is not automatically linked by the C compilation system.
Specify -ltecla on the cc command line to link with this library.
See libtecla(3LIB).



(3TSOL)


These functions constitute the Trusted Extensions library, libtsol, and
the Trusted Extensions network library, libtsnet. These libraries are
implemented as shared objects, libtsol.so and libtsnet.so, but are
not automatically linked by the C compilation system. Specify -ltsol or
-ltsnet on the cc command line to link with these libraries. See
libtsol(3LIB) and libtsnet(3LIB).



(3UUID)


These functions constitute the universally unique identifier library,
libuuid. This library is implemented as a shared object,
libuuid.so, but is not automatically linked by the C compilation system.
Specify -luuid on the cc command line to link with this library.
See libuuid(3LIB).



(3VOLMGT)


These functions constitute the volume management library, libvolmgt. This
library is implemented as a shared object, libvolmgt.so, but is not
automatically linked by the C compilation system. Specify -lvolmgt on the
cc command line to link with this library. See libvolmgt(3LIB).




 DEFINITIONS
A character is any bit pattern able to fit into a byte on the machine. In some
international languages, however, a "character" might require more than one
byte, and is represented in multi-bytes.


The null character is a character with value 0, conventionally represented in
the C language as \e\|0. A character array is a sequence of characters.
A null-terminated character array (a string) is a sequence of characters,
the last of which is the null character. The null string is a character array
containing only the terminating null character. A null pointer is the value
that is obtained by casting 0 into a pointer. C guarantees that this
value will not match that of any legitimate pointer, so many functions that
return pointers return NULL to indicate an error. The macro NULL is
defined in <stdio.h>. Types of the form size_t are defined in the
appropriate headers.

 MULTITHREADED APPLICATIONS
Both POSIX threads and Solaris threads can be used within the same application.
Their implementations are completely compatible with each other; however, only
POSIX threads guarantee portability to other POSIX-conforming environments.


The libpthread(3LIB) and libthread(3LIB) libraries are implemented
as filters on libc(3LIB).


When compiling a multithreaded application, the -mt option must be
specified on the command line.


There is no need for a multithreaded application to link with -lthread.
An application must link with -lpthread only when POSIX semantics for
fork(2) are desired. When an application is linked with -lpthread,
a call to fork() assumes the behavior fork1(2) rather than the
default behavior that forks all threads.


When compiling a POSIX-conforming application, either the _POSIX_C_SOURCE
or _POSIX_PTHREAD_SEMANTICS option must be specified on the command line.
For POSIX.1c-conforming applications, define the _POSIX_C_SOURCE flag to
be >= 199506L:

cc -mt [ flag... ] file... -D_POSIX_C_SOURCE=199506L -lpthread





For POSIX behavior with the Solaris fork() and fork1() distinction,
compile as follows:

cc -mt [ flag... ] file... -D_POSIX_PTHREAD_SEMANTICS





For Solaris threads behavior, compile as follows:

cc -mt [ flag... ] file...





Unsafe interfaces should be called only from the main thread to ensure the
application's safety.


MT-Safe interfaces are denoted in the ATTRIBUTES section of the functions
and libraries manual pages (see attributes(7)). If a manual page does not
state explicitly that an interface is MT-Safe, the user should assume that the
interface is unsafe.

 REALTIME APPLICATIONS
The environment variable LD_BIND_NOW must be set to a non-null value to
enable early binding. Refer to the "When Relocations are Processed" chapter in
Linker and Libraries Guide for additional information.

 FILES
INCDIR


usually /usr/include



LIBDIR


usually either /lib or /usr/lib (32-bit) or either /lib/64 or
/usr/lib/64 (64-bit)



LIBDIR/*.so


shared libraries




 ACKNOWLEDGMENTS
Sun Microsystems, Inc. gratefully acknowledges The Open Group for permission to
reproduce portions of its copyrighted documentation. Original documentation
from The Open Group can be obtained online at
http://www.opengroup.org/bookstore/.


The Institute of Electrical and Electronics Engineers and The Open Group, have
given us permission to reprint portions of their documentation.


In the following statement, the phrase ``this text'' refers to portions of the
system documentation.


Portions of this text are reprinted and reproduced in electronic form in the
SunOS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for
Information Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the event of
any discrepancy between these versions and the original IEEE and The Open Group
Standard, the original IEEE and The Open Group Standard is the referee
document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html.


This notice shall appear on any product containing this material.

 SEE ALSO
 ar (1),  ld (1),  fork (2),  stdio (3C),  attributes (7),  standards (7) 

Linker and Libraries Guide


Performance Profiling Tools


ANSI C Programmer's Guide

 DIAGNOSTICS
For functions that return floating-point values, error handling varies
according to compilation mode. Under the -Xt (default) option to
cc, these functions return the conventional values 0,
\(+-HUGE, or NaN when the function is undefined for the given
arguments or when the value is not representable. In the -Xa and
-Xc compilation modes, \(+-HUGE_VAL is returned instead of
\(+-HUGE. (HUGE_VAL and HUGE are defined in math.h to
be infinity and the largest-magnitude single-precision number, respectively.)

 NOTES
None of the functions, external variables, or macros should be redefined in the
user's programs. Any other name can be redefined without affecting the behavior
of other library functions, but such redefinition might conflict with a
declaration in an included header.


The headers in INCDIR provide function prototypes (function declarations
including the types of arguments) for most of the functions listed in this
manual. Function prototypes allow the compiler to check for correct usage of
these functions in the user's program. The lint program checker can also
be used and will report discrepancies even if the headers are not included with
#include statements. Definitions for Sections 2 and 3C are checked
automatically. Other definitions can be included by using the -l option
to lint. (For example, -lm includes definitions for libm.)
Use of lint is highly recommended. See the lint chapter in
Performance Profiling Tools


Users should carefully note the difference between STREAMS and stream.
STREAMS is a set of kernel mechanisms that support the development of network
services and data communication drivers. It is composed of utility routines,
kernel facilities, and a set of data structures. A stream is a file with
its associated buffering. It is declared to be a pointer to a type FILE
defined in <stdio.h>.


In detailed definitions of components, it is sometimes necessary to refer to
symbolic names that are implementation-specific, but which are not necessarily
expected to be accessible to an application program. Many of these symbolic
names describe boundary conditions and system limits.


In this section, for readability, these implementation-specific values are
given symbolic names. These names always appear enclosed in curly brackets to
distinguish them from symbolic names of other implementation-specific constants
that are accessible to application programs by headers. These names are not
necessarily accessible to an application program through a header, although
they can be defined in the documentation for a particular system.


In general, a portable application program should not refer to these symbolic
names in its code. For example, an application program would not be expected to
test the length of an argument list given to a routine to determine if it was
greater than {ARG_MAX}.