intro(3N)							     intro(3N)

NAME    [Toc]    [Back]

     intro - introduction to SVR4 networking functions and libraries

DESCRIPTION    [Toc]    [Back]

     This section describes functions found in the SVR4	networking library.
     Function declarations can be obtained from	the #include files indicated
     on	each page.  Certain major collections are identified by	a letter after
     the section number:

     The SVR4 networking functions are contained in a single libraries known
     as	the Network Services library, libnsl.

     The following functions constitute	the libnsl library:

	  netdir
	       Network Directory functions.  This contains look-up functions
	       and the access point to network directory libraries for various
	       network transports.

	  netselect
	       Network Selection routines.  These functions manipulate the
	       /etc/netconfig file and return entries.

	  nsl  Transport Level Interface (TLI).	 These functions contain the
	       implementation of X/OPEN's Transport Level Interface.

	  rexec
	       REXEC library interface

	  rpc  User-level Remote Procedure Call	library

	  saf  Service Access Facility library

	  yp   Network Information Service functions.  [The NIS	functions have
	       been moved to libc.]

DEFINITIONS    [Toc]    [Back]

     In	the Network Services library, netbuf is	a structure used in various
     TLI functions to send and receive data and	information.  netbuf is
     defined in	sys/tiuser.h, and includes the following members:

	  struct netbuf	{
	       unsigned	int maxlen;  /*	The physical size of the buffer	*/
	       unsigned	int len; /* The	number of bytes	in the buffer */
	       char *buf;  /* Points to	user input and/or output buffer	*/
	  };


     If	netbuf is used for output, the function	will set the user value	of len
     on	return.	 maxlen	generally has significance only	when buf is used to
     receive output from the TLI function.  In this case, it specifies the
     maximum value of len that can be set by the function.  If maxlen is not



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     large enough to hold the returned information, an TBUFOVFLW error will
     generally result.	However, certain functions may return part of the data
     and not generate an error.

FILES    [Toc]    [Back]

     INCDIR		 usually /usr/include
     LIBDIR		      usually /usr/ccs/lib
     LIBDIR<b>/libsocket.so (normally unused, see below)
     LIBDIR<b>/libnsl.so

SEE ALSO    [Toc]    [Back]

     intro(3)

NOTES    [Toc]    [Back]

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

     The header	files 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 may also be used and will report discrepancies even if
     the header	files are not included with #include statements.  Use of lint
     is	highly recommended.

     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 header	files.	These names are	not necessarily	accessible to
     an	application program through a header file, although they may 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}.

     There are 2 types of networking in	IRIX.

	  1)  BSD sockets implemented in the kernel, along with	SUN RPC	and
	  NIS (YP).  The functions that	implement these	calls are in libc [see
	  intro(3)].





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	  2)  SVR4-style STREAMS/TLI/DLPI networking (not sockets), along with
	  SVR4-style RPC.  SVR4-style RPC doesn't work with sockets, only with
	  the TLI.  Also, SVR4-style networking	does not support NIS.  The
	  functions that implement these calls are in libnsl, and to use them,
	  the code must	be compiled with :

	       cc -D_SVR4_TIRPC	prog.c -lnsl

	  eoe.sw.svr4net must be installed to use the TLI functionality.
	  eoe.sw.dlpi must be installed	to use the DLPI	(Data-link Provider
	  Interface) functionality.

	  In order to fully support the	MIPS ABI, there	is a library
	  (libsocket) that can be linked with explicitly.  There are no	header
	  file or semantic differences when using libsocket.  The MIPS ABIcompliant
 programs that use sockets must (in order to	be ABIcompliant)
 link with libsocket.  To compile such a program, use:

	       cc prog.c -lsocket

	  This library exists solely to	satisfy	the ABI; it uses the standard
	  IRIX socket services described above to implement the	specified
	  functionality.


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