The getservbyname(), getservbyport() and getservent() functions each return a pointer to a servent structure, the members of which contain the fields of an entry in the network services database.

The getservent() function reads the next entry of the database, opening a connection to the database if necessary.

The getservbyname() function searches the database from the beginning and finds the first entry for which the service name specified by name matches the s_name member and the protocol name specified by proto matches the s_proto member, opening a connection to the database if necessary. If proto is a null pointer, any value of the s_proto member will be matched.

The getservbyport() function searches the database from the beginning and finds the first entry for which the port specified by port matches the s_port member and the protocol name specified by proto matches the s_proto member, opening a connection to the database if necessary. If proto is a null pointer, any value of the s_proto member will be matched. The port argument must be in network byte order.

The setservent() function opens a connection to the database, and sets the next entry to the first entry. If the stayopen argument is non-zero, the net database will not be closed after each call to the getservent() function (either directly, or indirectly through one of the other getserv*() functions).

The endservent() function closes the database.

The port argument of getservbyport() need not be compatible with the port values of all address families.

The getservent(), getservbyname() and getservbyport() functions may return pointers to static data, which may be overwritten by subsequent calls to any of these functions.

These functions are generally used with the Internet address family.

On successful completion, getservbyname(), getservbyport() and getservent() return a pointer to a servent structure if the requested entry was found, and a null pointer if the end of the database was reached or the requested entry was not found. Otherwise, a null pointer is returned.

No errors are defined.

See attributes(5) for descriptions of the following attributes:

endhostent(3XNET), endprotoent(3XNET), htonl(3XNET), inet_addr(3XNET), attributes(5)