GETSERVENT

C Interface

        #include <netdb.h>



        struct servent *getservent()



        struct servent *getservbyname(name, proto)

        char *name, *proto;



        struct servent *getservbyport(port, proto)

        int port;

        char *proto;



        setservent(stayopen)

        int stayopen;



        endservent()

Description

The getservent, getservbyname, and getservbyport subroutines each return a pointer to an object with the following structure containing the broken-out fields of a line in the network services database, /etc/services.

   struct    servent {

        char *s_name;     /* official name of service */

        char **s_aliases; /* alias list               */

        long s_port;      /* port service resides at  */

        char *s_proto;    /* protocol to use          */

   };

The members of this structure are as follows:

s_name: The official name of the service.
s_aliases: A null-terminated list of alternate names for the service.
s_port: The port number at which the service resides. Port numbers are returned in network byte order.
s_proto: The name of the protocol to use when contacting the service.

The getservent subroutine reads the next line of the file, opening the file if necessary.

The setservent subroutine opens and rewinds the file. If the stayopen flag is non-zero, the services database is not closed after each call to getservent (either directly or indirectly through one of the other getserv calls).

The endservent subroutine closes the file.

The getservbyname and getservbyport subroutines sequentially search from the beginning of the file until a service name (among either the official names or the aliases) matching the parameter name or a port number matching the parameter port is found, or until EOF is encountered. If a non-NULL protocol name is also supplied (for example, tcp or udp), searches must also match the protocol.

Restrictions

All information is contained in a static area, so it must be copied if it is to be saved.

Return Value

The getservent, getservbyname, and getservbyport subroutines return a null pointer (0) on EOF or when they are unable to open SERVICES.NET.SYS.

MPE/iX Specific

The name of the services file on MPE/iX is SERVICES.NET.SYS, as opposed to /etc/services on HP-UX.

Author

UCB (University of California at Berkeley)

Files

SERVICES.NET.SYS