Add external logger interface.

include/cscore_c.h

@@ -54,6 +54,21 @@ enum CS_StatusValue {
   CS_SOURCE_IS_DISCONNECTED = -2005
 };
 
+//
+// Logging levels
+//
+enum CS_LogLevel {
+  CS_LOG_CRITICAL = 50,
+  CS_LOG_ERROR = 40,
+  CS_LOG_WARNING = 30,
+  CS_LOG_INFO = 20,
+  CS_LOG_DEBUG = 10,
+  CS_LOG_DEBUG1 = 9,
+  CS_LOG_DEBUG2 = 8,
+  CS_LOG_DEBUG3 = 7,
+  CS_LOG_DEBUG4 = 6
+};
+
 //
 // Pixel formats
 //
@@ -285,6 +300,13 @@ void CS_RemoveListener(CS_Listener handle, CS_Status* status);
 
 int CS_NotifierDestroyed(void);
 
+//
+// Logging Functions
+//
+typedef void (*CS_LogFunc)(unsigned int level, const char* file,
+                           unsigned int line, const char* msg);
+void CS_SetLogger(CS_LogFunc func, unsigned int min_level);
+
 //
 // Utility Functions
 //

include/cscore_cpp.h

@@ -278,6 +278,14 @@ void RemoveListener(CS_Listener handle, CS_Status* status);
 
 bool NotifierDestroyed();
 
+//
+// Logging Functions
+//
+typedef std::function<void(unsigned int level, const char* file,
+                           unsigned int line, const char* msg)>
+    LogFunc;
+void SetLogger(LogFunc func, unsigned int min_level);
+
 //
 // Utility Functions
 //