getprotobynumber()

Description

Get protocol information corresponding to a protocol number.

#include <winsock.h>

struct protoent FAR * PASCAL FAR getprotobynumber ( int number );

number

A protocol number, in host byte order.

Remarks

This function returns a pointer to a protoent structure as described above in getprotobyname(). The contents of the structure correspond to the given protocol number. 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, getprotobynumber() returns a pointer to the protoent 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

WSAAsyncGetProtoByNumber(), getprotobyname()

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