getservbyname()

Description

Get service information corresponding to a service name and protocol.

#include <winsock.h>

struct servent FAR * PASCAL FAR getservbyname ( const char FAR * name, const char FAR * proto);

name

A pointer to a service name.
proto
An optional pointer to a protocol name. If this is NULL, getservbyname() returns the first service entry for which the name matches the s_name or one of the s_aliases. Otherwise getservbyname() matches both the name and the proto.

Remarks

getservbyname() returns a pointer to the following structure which contains the name(s) and service number which correspond to the given service name.

struct servent {        char FAR *      s_name;
        char FAR * FAR *s_aliases;
        short           s_port;
        char FAR *      s_proto;
};

The members of this structure are:

s_name

Official name of the service.
s_aliases
A NULL-terminated array of alternate names.
s_port
The port number at which the service may be contacted. Port numbers are in network byte order.
s_proto
The name of the protocol to use when contacting the service.

The pointer which is returned points to a structure which is allocated by the Windows Sockets library. 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, getservbyname() 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

WSAAsyncGetServByName(), getservbyport()

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