diff --git a/lib/msg_log.cpp b/lib/msg_log.cpp
index d10ac4e7b0..9954150071 100644
--- a/lib/msg_log.cpp
+++ b/lib/msg_log.cpp
@@ -175,6 +175,36 @@ void MSG_LOG::printf_file(
     va_end(va);
 }
 
+void MSG_LOG::cond_printf(int conditional,int kind, const char* format, ...) {
+    if (conditional) {
+        va_list va;
+        va_start(va, format);
+        vprintf(kind, format, va);
+        va_end(va);
+    }
+}
+
+void MSG_LOG::cond_printf_multiline(
+    int conditional, int kind, const char* str, const char* prefix_format, ...
+) {
+    if (conditional) {
+        va_list va;
+        va_start(va, prefix_format);
+        vprintf_multiline(kind, str, prefix_format, va);
+        va_end(va);
+    }
+}
+
+void MSG_LOG::cond_printf_file(
+    int conditional, int kind, const char* filename, const char* prefix_format, ...
+) {
+    if (conditional) {
+        va_list va;
+        va_start(va, prefix_format);
+        vprintf_file(kind, filename, prefix_format, va);
+        va_end(va);
+    }
+}
 // These SCOPE_MSG_LOG functions are utility functions that call their
 // corresponding MSG_LOG functions with the same name, passing the KIND that
 // was specified on creation of the SCOPE_MSG_LOG object.
@@ -204,3 +234,33 @@ void SCOPE_MSG_LOG::printf_file(
     va_end(va);
 }
 
+void SCOPE_MSG_LOG::cond_printf(int conditional,const char* format, ...) {
+    if (conditional) {
+        va_list va;
+        va_start(va, format);
+        messages.vprintf(kind, format, va);
+        va_end(va);
+    }
+}
+
+void SCOPE_MSG_LOG::cond_printf_multiline(
+    int conditional,const char* str, const char* prefix_format, ...
+) {
+    if (conditional) {
+        va_list va;
+        va_start(va, prefix_format);
+        messages.vprintf_multiline(kind, str, prefix_format, va);
+        va_end(va);
+    }
+}
+
+void SCOPE_MSG_LOG::cond_printf_file(
+    int conditional,const char* filename, const char* prefix_format, ...
+) {
+    if (conditional) {
+        va_list va;
+        va_start(va, prefix_format);
+        messages.vprintf_file(kind, filename, prefix_format, va);
+        va_end(va);
+    }
+}
diff --git a/lib/msg_log.h b/lib/msg_log.h
index c112d25768..5de85093c1 100644
--- a/lib/msg_log.h
+++ b/lib/msg_log.h
@@ -62,6 +62,11 @@ public:
     void vprintf_multiline(int kind, const char* str, const char* prefix_format, va_list va);
     void vprintf_file(int kind, const char* filename, const char* prefix_format, va_list va);
 
+    void cond_printf(int conditional,int kind, const char* format, ...) __attribute__ ((format (printf, 4, 5)));
+    void cond_printf_multiline(int conditional,int kind, const char* str, const char* prefix_format, ...) __attribute__ ((format (printf, 5, 6)));
+    void cond_printf_file(int conditional, int kind, const char* str, const char* prefix_format, ...) __attribute__ ((format (printf, 5, 6)));
+
+
 protected:
 
     virtual const char* v_format_kind(int kind) const = 0;
@@ -88,6 +93,10 @@ public:
     void printf(const char* format, ...) __attribute__ ((format (printf, 2, 3)));
     void printf_multiline(const char* str, const char* prefix_format, ...) __attribute__ ((format (printf, 3, 4)));
     void printf_file(const char* filename, const char* prefix_format, ...) __attribute__ ((format (printf, 3, 4)));
+
+    void cond_printf(int conditional, const char* format, ...) __attribute__ ((format (printf, 3, 4)));
+    void cond_printf_multiline(int conditional, const char* str, const char* prefix_format, ...) __attribute__ ((format (printf, 4, 5)));
+    void cond_printf_file(int conditional, const char* str, const char* prefix_format, ...) __attribute__ ((format (printf, 4, 5)));
 };
 
 #if _MSC_VER >= 1300