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.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date. The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein. The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" References consulted:
.\" Linux libc source code
.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
.\" 386BSD man pages
.\" Modified Sat Jul 24 19:19:11 1993 by Rik Faith (faith@cs.unc.edu)
.\" Modified Wed Oct 18 20:23:54 1995 by Martin Schulze <joey@infodrom.north.de>
.\" Modified Mon Apr 22 01:50:54 1996 by Martin Schulze <joey@infodrom.north.de>
.\" 2001-07-25 added a clause about NULL proto (Martin Michlmayr or David N. Welton)
.\"
.TH GETSERVENT 3 2001-07-25 "GNU" "Linux Programmer's Manual"
.SH NAME
getservent, getservbyname, getservbyport, setservent, endservent \-
get service entry
.SH SYNOPSIS
.nf
.B #include <netdb.h>
.sp
.B struct servent *getservent(void);
.sp
.BI "struct servent *getservbyname(const char *" name ", const char *" proto );
.sp
.BI "struct servent *getservbyport(int " port ", const char *" proto );
.sp
.BI "void setservent(int " stayopen );
.sp
.B void endservent(void);
.fi
.SH DESCRIPTION
The
.BR getservent ()
function reads the next line from the file
\fI/etc/services\fP and returns a structure \fIservent\fP containing
the broken out fields from the line.
The \fI/etc/services\fP file
is opened if necessary.
.PP
The
.BR getservbyname ()
function returns a \fIservent\fP structure
for the line from \fI/etc/services\fP that matches the service
\fIname\fP using protocol \fIproto\fP.
If \fIproto\fP is NULL, any protocol will be matched.
.PP
The
.BR getservbyport ()
function returns a \fIservent\fP structure
for the line that matches the port \fIport\fP given in network byte order
using protocol \fIproto\fP.
If \fIproto\fP is NULL, any protocol will be matched.
.PP
The
.BR setservent ()
function opens and rewinds the
\fI/etc/services\fP file.
If \fIstayopen\fP is true (1), then the
file will not be closed between calls to
.BR getservbyname ()
and
.BR getservbyport ().
.PP
The
.BR endservent ()
function closes \fI/etc/services\fP.
.PP
The \fIservent\fP structure is defined in \fI<netdb.h>\fP as follows:
.sp
.RS
.nf
struct servent {
char *s_name; /* official service name */
char **s_aliases; /* alias list */
int s_port; /* port number */
char *s_proto; /* protocol to use */
}
.fi
.RE
.PP
The members of the \fIservent\fP structure are:
.TP
.I s_name
The official name of the service.
.TP
.I s_aliases
A zero terminated list of alternative names for the service.
.TP
.I s_port
The port number for the service given in network byte order.
.TP
.I s_proto
The name of the protocol to use with this service.
.SH "RETURN VALUE"
The
.BR getservent (),
.BR getservbyname ()
and
.BR getservbyport ()
functions return the \fIservent\fP structure, or a NULL pointer if an
error occurs or the end of the file is reached.
.SH FILES
.TP
.I /etc/services
services database file
.SH "CONFORMING TO"
4.3BSD, POSIX.1-2001.
.SH "SEE ALSO"
.BR getnetent (3),
.BR getprotoent (3),
.BR services (5)
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