varnishlog: Document impotent options without -w

bin/varnishlog/varnishlog_options.h

@@ -32,22 +32,24 @@
 #include "vapi/vapi_options.h"
 #include "vut_options.h"
 
+#define LOG_NOTICE_w " This option has no effect without the -w option."
+
 #define LOG_OPT_a							\
 	VOPT("a", "[-a]", "Append to file",				\
 	    "When writing output to a file with the -w option, append"	\
-	    " to it rather than overwrite it."				\
+	    " to it rather than overwrite it." LOG_NOTICE_w		\
 	)
 
 #define LOG_OPT_A							\
 	VOPT("A", "[-A]", "Text output",				\
 	    "When writing output to a file with the -w option, output"	\
-	    " data in ascii format."					\
+	    " data in ascii format." LOG_NOTICE_w			\
 	)
 
 #define LOG_OPT_u							\
 	VOPT("u", "[-u]", "Unbuffered output",				\
 	    "When writing output to a file with the -w option, output"	\
-	    " data is not buffered."					\
+	    " data is not buffered." LOG_NOTICE_w			\
 	)
 
 #define LOG_OPT_w							\

bin/varnishtest/tests/u00006.vtc

@@ -9,7 +9,7 @@ varnish v1 -vcl+backend {} -start
 
 # We use this to make sure we know there is a "0 CLI" in the binary log.
 process p1 {
-	exec varnishlog -n ${v1_name} -g raw -u -A
+	exec varnishlog -n ${v1_name} -g raw -u -A -w -
 } -start
 
 shell {