server FEATURE ssh session creation functions

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diff --git a/src/log_p.h b/src/log_p.h
index f62bdc5..c6f29f2 100644
--- a/src/log_p.h
+++ b/src/log_p.h
@@ -52,5 +52,6 @@
 #define DBG(format,args...) if(verbose_level>=NC_VERB_DEBUG){prv_printf(NC_VERB_DEBUG,format,##args);}
 
 #define ERRMEM ERR("Memory reallocation failed (%s:%d).", __FILE__, __LINE__)
+#define ERRARG ERR("%s: invalid arguments.", __func__)
 
 #endif /* NC_LOG_PRIVATE_H_ */