getservbyport()

The getservbyport() call searches the hlq.ETC.SERVICES data set for the specified port number. Searches for a port number must match the protocol, if a protocol is stated.

The getservbyport() call returns a pointer to a servent structure for the port number specified on the call.

#include <manifest.h>
#include <netdb.h>
struct servent *getservbyport(int port, char *proto)

Parameter: Description
port: Port number
proto: Points to the specified protocol

The servent structure is defined in the NETDB.H header file and contains the following elements:

Element: Description
s_name: The official name of the service
s_aliases: An array, terminated with a NULL pointer, of alternative names for the service
s_port: The port number of the service
s_proto: The protocol required to contact the service

Return values

The return value points to static data that is overwritten by subsequent calls. Points to a servent structure indicates success. A NULL pointer indicates an error or end-of-file. When a NULL pointer or 0 is returned, the value of errno is indeterminate, and therefore, the output from a tcperror() call cannot be validated.

Related calls

endservant(), getservbyname(), getservent(), setservent()