1 files changed, 14 insertions, 1 deletions
diff --git a/src/cc4group.h b/src/cc4group.h
index d2d978c..d81e84a 100644
--- a/src/cc4group.h
+++ b/src/cc4group.h
@@ -29,7 +29,7 @@
 //    the directory separator used for all entry paths in cc4group is "/" _regardless of the platform_. yes, you better watch out Windows users!
 //    in contrast to paths names are only the the name of the entry itself, not the whole path
 //  - to free all resources used by the group when it is not needed anymore, call cc4group.delete with the group pointer and discard it afterwards (i.e. don't use it anymore)
-//  - all functions, except cc4group.new, cc4group.setLazy, cc4group.openAsChild, cc4group.delete and cc4group.setTmpMemoryStrategy (where the latter two can't fail) follow the same scheme
+//  - all functions, except cc4group.new, cc4group.setLazy, cc4group.openAsChild, cc4group.delete, cc4group.setWarningCallback and cc4group.setTmpMemoryStrategy (where the latter three can't fail) follow the same scheme
 //    all of them can fail, either caused by wrong arguments or by things outside of the applications control
 //    they all return _true_ if everything went well and _false_ if any error occured
 //    information about the error (incredibly useful for debugging or asking for help with problems) can be obtained by using one the cc4group.getError* functions
@@ -173,6 +173,13 @@ typedef bool (*CC4Group_ReadSetupCallback)(void* const arg);
 typedef bool (*CC4Group_WriteCallback)(const void* const data, size_t const size, void* const arg);
 
 
+
+// callback type for receiving warnings
+// whenever a warning is triggered, the callback will be called with the triggering group
+// and a format string and format arguments that are destined for some *printf function
+typedef void (*CC4Group_WarningCallback)(const CC4Group* const group, const char* const format, ...);
+
+
 // this is the main API struct of cc4group
 // it contains all available methods and constants
 typedef struct {
@@ -212,6 +219,12 @@ typedef struct {
 	// for details, look at the description of CC4Group_TmpMemoryStrategy
 	void (*setTmpMemoryStrategy)(const CC4Group_TmpMemoryStrategy strategy);
 
+	// sets the global warning callback
+	// the default callback prints warnings to stderr; it can be restored by calling setWarningCallback with callback as NULL
+	// NOTE: this is a static method (i.e. it is used without any object)
+	// this will affect all groups in any state
+	void (*setWarningCallback)(const CC4Group_WarningCallback callback);
+
 
 	// allocates and initializes a new group object, like the operator new
 	// NULL may be returned if the memory allocation (malloc) fails; in this case errno contains additional error information