getservbyport()

Description

Get service information corresponding to a port and protocol.

#include <winsock.h>

struct servent FAR * PASCAL FAR getservbyport ( int port, const char FAR * proto);

port

The port for a service, in network byte order.
proto
An optional pointer to a protocol name. If this is NULL, getservbyport() returns the first service entry for which the port matches the s_port. Otherwise getservbyport() matches both the port and the proto.

Remarks

getservbyport() returns a pointer a servent structure as described above for getservbyname(). The pointer which is returned points to a structure which is allocated by the Windows Sockets implementation. The application must never attempt to modify this structure or to free any of its components. Furthermore, only one copy of this structure is allocated per thread, and so the application should copy any information which it needs before issuing any other Windows Sockets API calls.

Return Value

If no error occurs, getservbyport() returns a pointer to the servent structure described above. Otherwise it returns a NULL pointer and a specific error number may be retrieved by calling WSAGetLastError()

Error Codes

WSANOTINITIALISED

A successful WSAStartup() must occur before using this API.
WSAENETDOWN
The Windows Sockets implementation has detected that the network subsystem has failed.
WSANO_RECOVERY
Non recoverable errors, FORMERR, REFUSED, NOTIMP.
WSANO_DATA
Valid name, no data record of requested type.
WSAEINPROGRESS
A blocking Windows Sockets operation is in progress.
WSAEINTR
The (blocking) call was canceled via WSACancelBlockingCall()

See Also

WSAAsyncGetServByPort(), getservbyname()

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