.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\"
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.\" References consulted:
.\" Linux libc source code
.\" 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 "BSD" "Linux Programmer's Manual"
+.TH GETSERVENT 3 2017-09-15 "GNU" "Linux Programmer's Manual"
.SH NAME
getservent, getservbyname, getservbyport, setservent, endservent \-
-get service entry
+get service entry
.SH SYNOPSIS
.nf
.B #include <netdb.h>
-.sp
+.PP
.B struct servent *getservent(void);
-.sp
+.PP
.BI "struct servent *getservbyname(const char *" name ", const char *" proto );
-.sp
+.PP
.BI "struct servent *getservbyport(int " port ", const char *" proto );
-.sp
+.PP
.BI "void setservent(int " stayopen );
-.sp
+.PP
.B void endservent(void);
.fi
.SH DESCRIPTION
-The \fBgetservent\fP() 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.
+The
+.BR getservent ()
+function reads the next entry from the services database (see
+.BR services (5))
+and returns a
+.I servent
+structure containing
+the broken-out fields from the entry.
+A connection is opened to the database if necessary.
.PP
-The \fBgetservbyname\fP() 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.
+The
+.BR getservbyname ()
+function returns a
+.I servent
+structure
+for the entry from the database
+that matches the service
+.I name
+using protocol
+.IR proto .
+If
+.I proto
+is NULL, any protocol will be matched.
+A connection is opened to the database if necessary.
.PP
-The \fBgetservbyport\fP() 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.
+The
+.BR getservbyport ()
+function returns a
+.I servent
+structure
+for the entry from the database
+that matches the port
+.I port
+(given in network byte order)
+using protocol
+.IR proto .
+If
+.I proto
+is NULL, any protocol will be matched.
+A connection is opened to the database if necessary.
.PP
-The \fBsetservent\fP() 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 \fBgetservbyname\fP() and
-\fBgetservbyport\fP().
+The
+.BR setservent ()
+function opens a connection to the database,
+and sets the next entry to the first entry.
+If
+.I stayopen
+is nonzero,
+then the connection to the database
+will not be closed between calls to one of the
+.BR getserv* ()
+functions.
.PP
-The \fBendservent\fP() function closes \fI/etc/services\fP.
+The
+.BR endservent ()
+function closes the connection to the database.
.PP
-The \fIservent\fP structure is defined in \fI<netdb.h>\fP as follows:
-.sp
-.RS
-.nf
-.ne 6
-.ta 8n 16n 32n
+The
+.I servent
+structure is defined in
+.I <netdb.h>
+as follows:
+.PP
+.in +4n
+.EX
struct servent {
- char *s_name; /* official service name */
- char **s_aliases; /* alias list */
- int s_port; /* port number */
- char *s_proto; /* protocol to use */
+ char *s_name; /* official service name */
+ char **s_aliases; /* alias list */
+ int s_port; /* port number */
+ char *s_proto; /* protocol to use */
}
-.ta
-.fi
-.RE
+.EE
+.in
.PP
-The members of the \fIservent\fP structure are:
+The members of the
+.I servent
+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.
+A NULL-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 \fBgetservent\fP(), \fBgetservbyname\fP() and \fBgetservbyport\fP()
-functions return the \fIservent\fP structure, or a NULL pointer if an
+.SH RETURN VALUE
+The
+.BR getservent (),
+.BR getservbyname ()
+and
+.BR getservbyport ()
+functions return a pointer to a
+statically allocated
+.I servent
+structure, or NULL 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
-.SH "SEE ALSO"
+.SH ATTRIBUTES
+For an explanation of the terms used in this section, see
+.BR attributes (7).
+.TS
+allbox;
+lbw15 lb lbw25
+l l l.
+Interface Attribute Value
+T{
+.BR getservent ()
+T} Thread safety T{
+MT-Unsafe race:servent
+.br
+race:serventbuf locale
+T}
+T{
+.BR getservbyname ()
+T} Thread safety T{
+MT-Unsafe race:servbyname
+.br
+locale
+T}
+T{
+.BR getservbyport ()
+T} Thread safety T{
+MT-Unsafe race:servbyport
+.br
+locale
+T}
+T{
+.BR setservent (),
+.br
+.BR endservent ()
+T} Thread safety T{
+MT-Unsafe race:servent
+.br
+locale
+T}
+.TE
+.sp 1
+In the above table,
+.I servent
+in
+.I race:servent
+signifies that if any of the functions
+.BR setservent (),
+.BR getservent (),
+or
+.BR endservent ()
+are used in parallel in different threads of a program,
+then data races could occur.
+.SH CONFORMING TO
+POSIX.1-2001, POSIX.1-2008, 4.3BSD.
+.SH SEE ALSO
.BR getnetent (3),
.BR getprotoent (3),
+.BR getservent_r (3),
.BR services (5)
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