#if defined(_WIN32)
/*
 * On Windows, we need to do proper Unicode->UTF-8 conversion.
 */

typedef struct ThreadSpecificData_Sockets {
    bool initialized;
    Tcl_DString errorMsg;	/* UTF-8 encoded error-message */
} ThreadSpecificData;
static Tcl_ThreadDataKey dataKey;

#undef gai_strerror
static const char *
gai_strerror(
    int code)
{
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    if (tsdPtr->initialized) {
	Tcl_DStringSetLength(&tsdPtr->errorMsg, 0);
    } else {
	Tcl_DStringInit(&tsdPtr->errorMsg);
	tsdPtr->initialized = true;
    }
    Tcl_WCharToUtfDString(gai_strerrorW(code), -1, &tsdPtr->errorMsg);
    return Tcl_DStringValue(&tsdPtr->errorMsg);
}
#endif

/*

 *----------------------------------------------------------------------
 *
 * TclCreateSocketAddress --
 *
 *	This function initializes a sockaddr structure for a host and port.
 *
 * Results:
 *	true if the host was valid, false if the host could not be converted
 *	to an IP address.
 *
 * Side effects:
 *	Fills in the *sockaddrPtr structure.
 *
 *----------------------------------------------------------------------
 */


bool
TclCreateSocketAddress(
    Tcl_Interp *interp,		/* Interpreter for querying the desired socket
				 * family */
    struct addrinfo **addrlist,	/* Socket address list */
    const char *host,		/* Host. NULL implies INADDR_ANY */
    int port,			/* Port number */
    int willBind,		/* Is this an address to bind() to or to
				 * connect() to? */
    const char **errorMsgPtr)	/* Place to store the error message detail, if
				 * available. */
{
    char *native = NULL, portbuf[TCL_INTEGER_SPACE], *portstring;
    Tcl_DString ds;

    if (host != NULL) {
	if (Tcl_UtfToExternalDStringEx(interp, NULL, host, -1, 0, &ds,
		NULL) != TCL_OK) {
	    Tcl_DStringFree(&ds);
	    return false;
	}
	native = Tcl_DStringValue(&ds);
    }

    /*
     * Workaround for OSX's apparent inability to resolve "localhost", "0"
     * when the loopback device is the only available network interface.

    if (result != 0) {
	*errorMsgPtr =
#ifdef EAI_SYSTEM	/* Doesn't exist on Windows */
		(result == EAI_SYSTEM) ? Tcl_PosixError(interp) :
#endif /* EAI_SYSTEM */
		gai_strerror(result);
	return false;
    }

    /*
     * Put IPv4 addresses before IPv6 addresses to maximize backwards
     * compatibility of [fconfigure -sockname] output.
     *
     * There might be more elegant/efficient ways to do this.

	    v6ptr->ai_next = NULL;
	}
	if (v4head != NULL) {
	    v4ptr->ai_next = *addrlist;
	    *addrlist = v4head;
	}
    }
    return true;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_OpenTcpServer --
 *