#include <netdb.h>
struct servent *getservbyport ( Port, Protocol)
int Port;
char *Protocol;
Attention: Do not use the getservbyport subroutine in a multithreaded environment.
The getservbyport subroutine retrieves an entry from the /etc/services file using a port number as a search key.
An application program can use the getservbyport subroutine to access a service, service aliases, the protocol for the service, and a protocol port number for the service.
The getservbyport subroutine searches the services file sequentially from the beginning of the file until it finds one of the following:
Upon locating a matching protocol and port number or upon locating a matching protocol only if the Port parameter value equals 0, the getservbyport subroutine returns a pointer to a servent structure, which contains fields for a line of information in the /etc/services file. The netdb.h file defines the servent structure and structure fields.
Use the endservent subroutine to close the /etc/services file.
| Port | Specifies the port where a service resides. |
| Protocol | Specifies a protocol for use with the service. |
Upon successful completion, the getservbyport subroutine returns a pointer to a servent structure.
Note: The return value points to static data that is overwritten by subsequent calls.
If an error occurs or the end of the file is reached, the getservbyport subroutine returns a null pointer.
The getservbyport subroutine is part of Base Operating System (BOS) Runtime.
All applications containing the getservbyport subroutine must be compiled with _BSD set to a specific value. Acceptable values are 43 and 44. In addition, all socket applications must include the BSD libbsd.a library.
| /etc/services | |
| Contains service names. | |
The endprotoent subroutine, endservent subroutine, getprotobyname subroutine, getprotobynumber subroutine, getprotoent subroutine, getservbyname subroutine, getservent subroutine, setprotoent subroutine, setservent subroutine.
Sockets Overview in AIX 5L Version 5.1 Communications Programming Concepts.