.\" 	@(#)getnetconfig.3n 1.28 93/06/02 SMI; from SVr4
.\"	$NetBSD: getnetconfig.3,v 1.7 2003/04/16 13:34:43 wiz Exp $
.\" Copyright 1989 AT&T
.Dd April 22, 2000
.Dt GETNETCONFIG 3
.Os
.Sh NAME
.Nm getnetconfig ,
.Nm setnetconfig ,
.Nm endnetconfig ,
.Nm getnetconfigent ,
.Nm freenetconfigent ,
.Nm nc_perror ,
.Nm nc_sperror
.Nd get network configuration database entry
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In netconfig.h
.Ft struct netconfig *
.Fn getnetconfig "void *handlep"
.Ft void *
.Fn setnetconfig "void"
.Ft int
.Fn endnetconfig "void *handlep"
.Ft struct netconfig *
.Fn getnetconfigent "const char *netid"
.Ft void
.Fn freenetconfigent "struct netconfig *netconfigp"
.Ft void
.Fn nc_perror "const char *msg"
.Ft char *
.Fn nc_sperror "void"
.Sh DESCRIPTION
The library routines described on this page
provide the application access to
the system network configuration database,
.Pa /etc/netconfig .
.Bd -literal
struct netconfig {
        char *nc_netid;              /* Network ID */
        unsigned long nc_semantics;  /* Semantics */
        unsigned long nc_flag;       /* Flags */
        char *nc_protofmly;          /* Protocol family */
        char *nc_proto;              /* Protocol name */
        char *nc_device;             /* Network device pathname */
        unsigned long nc_nlookups;   /* Number of directory lookup libs */
        char **nc_lookups;           /* Names of the libraries */
};
.Ed
.Pp
.Fn getnetconfig
returns a pointer to the
current entry in the
.Pa netconfig
database, formatted as a struct netconfig.
Successive calls will return successive netconfig
entries in the netconfig database.
.Fn getnetconfig
can be used to search the entire netconfig
file.
.Fn getnetconfig
returns
.Dv NULL
at the end of the file.
.Fa handlep
is the handle obtained through
.Fn setnetconfig .
.Pp
A call to
.Fn setnetconfig
has the effect of ``binding'' to or
``rewinding'' the netconfig database.
.Fn setnetconfig
must be called before the first call to
.Fn getnetconfig
and may be called at any other time.
.Fn setnetconfig
need not be called before a call to
.Fn getnetconfigent .
.Fn setnetconfig
returns a unique handle to be used by
.Fn getnetconfig .
.Pp
.Fn endnetconfig
should be called when processing is complete to release resources for reuse.
.Fa handlep
is the handle obtained through
.Fn setnetconfig .
Programmers should be aware, however, that the last call to
.Fn endnetconfig
frees all memory allocated by
.Fn getnetconfig
for the
struct netconfig data structure.
.Fn endnetconfig
may not be called before
.Fn setnetconfig .
.Pp
.Fn getnetconfigent
returns a pointer
to the netconfig structure corresponding
to
.Fa netid .
It returns
.Dv NULL
if
.Fa netid
is invalid
(that is, does not name an entry in the netconfig database).
.Pp
.Fn freenetconfigent
frees the netconfig structure pointed to by
.Fa netconfigp
(previously returned by
.Fn getnetconfigent ) .
.Pp
.Fn nc_perror
prints a message to the standard error indicating why any of the
above routines failed.
The message is prepended with the string
.Fa msg
and a colon.
A newline character is appended at the end of the message.
.Pp
.Fn nc_sperror
is similar to
.Fn nc_perror
but instead of sending the message
to the standard error, will return a pointer to a string that
contains the error message.
.Pp
.Fn nc_perror
and
.Fn nc_sperror
can also be used with the
.Va NETPATH
access routines defined in
.Xr getnetpath 3 .
.Sh RETURN VALUES
.Fn setnetconfig
returns a unique handle to be used by
.Fn getnetconfig .
In the case of an error,
.Fn setnetconfig
returns NULL and
.Fn nc_perror
or
.Fn nc_sperror
can be used to print the reason for failure.
.Pp
.Fn getnetconfig
returns a pointer to the current entry in the netconfig
database, formatted as a struct netconfig.
.Fn getnetconfig
returns NULL
at the end of the file, or upon failure.
.Pp
.Fn endnetconfig
returns 0 on success and -1 on failure
(for example, if
.Fn setnetconfig
was not called previously).
.Pp
On success,
.Fn getnetconfigent
returns a pointer to the
.Li struct netconfig
structure corresponding to
.Ar netid ;
otherwise it returns
.Dv NULL .
.Pp
.Fn nc_sperror
returns a pointer to a buffer which contains the error message string.
This buffer is overwritten on each call.
In multithreaded applications, this buffer is
implemented as thread-specific data.
.Sh FILES
.Pa /etc/netconfig
.Sh SEE ALSO
.Xr getnetpath 3 ,
.Xr netconfig 5