getservbyname
The Windows
Sockets getsservbyname function gets service information corresponding
to a service name and protocol.
struct servent FAR * getservbyname (
|
const char
FAR * name, |
|
|
const char
FAR * proto |
|
|
); |
|
Parameters
name
[in] A
pointer to a null terminated service name.
proto
[in] An
optional pointer to a null terminated protocol name. If this pointer 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.
All strings are null terminated.
struct servent {
char FAR
* s_name;
char FAR *
FAR * s_aliases;
short s_port;
char FAR
* s_proto;
};
The members
of this structure are:
|
Element |
Usage |
|
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 can be contacted. Port numbers are returned 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 function calls.
Return Values
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 can be retrieved by calling WSAGetLastError.
Error Codes
|
WSANOTINITIALISED |
A
successful WSAStartup must occur before using this function. |
|
WSAENETDOWN |
The network
subsystem has failed. |
|
WSAHOST_NOT_FOUND |
Authoritative
Answer Service not found. |
|
WSATRY_AGAIN |
Non-Authoritative
Service not found, or server failure. |
|
WSANO_RECOVERY |
Nonrecoverable
errors, the services database is not accessible. |
|
WSANO_DATA |
Valid name,
no data record of requested type. |
|
WSAEINPROGRESS |
A blocking
Windows Sockets 1.1 call is in progress, or the service provider is still
processing a callback function. |
|
WSAEINTR |
The
(blocking) call was canceled through WSACancelBlockingCall. |
See Also