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\" @(#)getservent.3 8.4 (Berkeley) 5/25/95
\"
Dd December 3, 2022
Dt GETSERVENT 3
Os
Sh NAME
Nm getservent ,
Nm getservbyport ,
Nm getservbyname ,
Nm setservent ,
Nm endservent
Nd get service entry
Sh LIBRARY
Lb libc
Sh SYNOPSIS
In netdb.h
Ft struct servent *
Fn getservent
Ft struct servent *
Fn getservbyname "const char *name" "const char *proto"
Ft struct servent *
Fn getservbyport "int port" "const char *proto"
Ft void
Fn setservent "int stayopen"
Ft void
Fn endservent void
Sh DESCRIPTION
The
Fn getservent ,
Fn getservbyname ,
and
Fn getservbyport
functions
each return a pointer to an object with the
following structure
containing the broken-out
fields of a line in the network services data base,
Pa /etc/services .
Bd -literal -offset indent
struct servent {
char *s_name; /* official name of service */
char **s_aliases; /* alias list */
int s_port; /* port service resides at */
char *s_proto; /* protocol to use */
};
Ed
Pp
The members of this structure are:
Bl -tag -width s_aliases
It Fa s_name
The official name of the service.
It Fa s_aliases
A NULL terminated list of alternative names for the service.
It Fa s_port
The port number at which the service resides.
Port numbers must be given and are returned in network byte order.
It Fa s_proto
The name of the protocol to use when contacting the
service.
El
Pp
The
Fn getservent
function
reads the next line of the file, opening the file if necessary.
Pp
The
Fn setservent
function
opens and rewinds the file. If the
Fa stayopen
flag is non-zero,
the net data base will not be closed after each call to
Fn getservbyname
or
Fn getservbyport .
Pp
The
Fn endservent
function
closes the file.
Pp
The
Fn getservbyname
and
Fn getservbyport
functions
sequentially search from the beginning
of the file until a matching
protocol name or
port number is found,
or until
Dv EOF
is encountered.
If a protocol name is also supplied (non-\c
Dv NULL ) ,
searches must also match the protocol.
Sh FILES
Bl -tag -width /etc/services -compact
It Pa /etc/services
It Pa /var/db/services.cdb
El
Sh RETURN VALUES
Null pointer is returned on
Dv EOF
or error.
Sh SEE ALSO
Xr getprotoent 3 ,
Xr services 5 ,
Xr services_mkdb 8
Sh HISTORY
The
Fn getservent ,
Fn getservbyport ,
Fn getservbyname ,
Fn setservent ,
and
Fn endservent
functions appeared in
Bx 4.2 .
Sh BUGS
These functions use static data storage;
if the data is needed for future use, it should be
copied before any subsequent calls overwrite it.
Expecting port numbers to fit in a 32 bit
quantity is probably naive.
