Windows Event Log, error output

Adding more Event Log support, and modifying the loggers so they return
errors in their operational functions.

logging/funcs_std.go

@@ -2,26 +2,45 @@ package logging
 
 import (
 	"fmt"
-	"log"
+	`log`
+	`os`
+	`strings`
 )
 
-// Setup sets up/configures a StdLogger and prepares it for use.
-func (l *StdLogger) Setup() {
+/*
+	Setup sets up/configures a StdLogger and prepares it for use.
+	err will always be nil; it's there for interface-compat.
+*/
+func (l *StdLogger) Setup() (err error) {
 
-	l.Logger = log.Default()
-	l.Logger.SetPrefix(l.Prefix + " ")
+	// This uses a shared handle across the import. We don't want that.
+	// l.Logger = log.Default()
+	if l.Prefix != "" {
+		l.Prefix = strings.TrimRight(l.Prefix, " ") + " "
+		// l.Logger.SetPrefix(l.Prefix)
+	}
+	// (stdlib).log.std is returned by log.Default(), which uses os.Stderr.
+	l.Logger = log.New(os.Stderr, l.Prefix, l.LogFlags)
+
+	return
 }
 
-// Shutdown cleanly shuts down a StdLogger.
-func (l *StdLogger) Shutdown() {
+/*
+	Shutdown cleanly shuts down a StdLogger.
+	err will always be nil; it's there for interface-compat.
+*/
+func (l *StdLogger) Shutdown() (err error) {
 
 	// NOOP
-	_ = ""
 
+	return
 }
 
-// GetPrefix returns the prefix used by this StdLogger.
-func (l *StdLogger) GetPrefix() (prefix string) {
+/*
+	GetPrefix returns the prefix used by this StdLogger.
+	err will always be nil; it's there for interface-compat.
+*/
+func (l *StdLogger) GetPrefix() (prefix string, err error) {
 
 	prefix = l.Prefix
 
@@ -31,15 +50,28 @@ func (l *StdLogger) GetPrefix() (prefix string) {
 /*
 	DoDebug sets the debug state of this StdLogger.
 	Note that this merely acts as a *safety filter* for debug messages to avoid sensitive information being written to the log.
+	err will always be nil; it's there for interface-compat.
 */
-func (l *StdLogger) DoDebug(d bool) {
+func (l *StdLogger) DoDebug(d bool) (err error) {
+
 	l.EnableDebug = d
+
+	return
 }
 
-// SetPrefix sets the prefix for this StdLogger.
-func (l *StdLogger) SetPrefix(prefix string) {
-	l.Prefix = prefix + " "
-	l.Logger.SetPrefix(prefix + " ")
+/*
+	SetPrefix sets the prefix for this StdLogger.
+	err will always be nil; it's there for interface-compat.
+*/
+func (l *StdLogger) SetPrefix(prefix string) (err error) {
+
+	l.Prefix = prefix
+	if prefix != "" {
+		l.Prefix = strings.TrimRight(l.Prefix, " ") + " "
+	}
+	l.Logger.SetPrefix(l.Prefix)
+
+	return
 }
 
 // Alert writes an ALERT-level message to this StdLogger.