diff --git a/include/libdivecomputer/context.h b/include/libdivecomputer/context.h
index 10f21b4..861dbeb 100644
--- a/include/libdivecomputer/context.h
+++ b/include/libdivecomputer/context.h
@@ -39,6 +39,8 @@ typedef enum dc_loglevel_t {
 	DC_LOGLEVEL_ALL
 } dc_loglevel_t;
 
+typedef void (*dc_logfunc_t) (dc_context_t *context, dc_loglevel_t loglevel, const char *file, unsigned int line, const char *function, const char *message, void *userdata);
+
 dc_status_t
 dc_context_new (dc_context_t **context);
 
@@ -48,6 +50,9 @@ dc_context_free (dc_context_t *context);
 dc_status_t
 dc_context_set_loglevel (dc_context_t *context, dc_loglevel_t loglevel);
 
+dc_status_t
+dc_context_set_logfunc (dc_context_t *context, dc_logfunc_t logfunc, void *userdata);
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
diff --git a/src/context.c b/src/context.c
index f9d720a..2e0c62b 100644
--- a/src/context.c
+++ b/src/context.c
@@ -28,8 +28,19 @@
 
 struct dc_context_t {
 	dc_loglevel_t loglevel;
+	dc_logfunc_t logfunc;
+	void *userdata;
+	char msg[4096];
 };
 
+static void
+logfunc (dc_context_t *context, dc_loglevel_t loglevel, const char *file, unsigned int line, const char *function, const char *msg, void *userdata)
+{
+	const char *loglevels[] = {"NONE", "ERROR", "WARNING", "INFO", "DEBUG", "ALL"};
+
+	fprintf (stderr, "%s: %s [in %s:%d (%s)]\n", loglevels[loglevel], msg, file, line, function);
+}
+
 dc_status_t
 dc_context_new (dc_context_t **out)
 {
@@ -43,6 +54,10 @@ dc_context_new (dc_context_t **out)
 		return DC_STATUS_NOMEMORY;
 
 	context->loglevel = DC_LOGLEVEL_WARNING;
+	context->logfunc = logfunc;
+	context->userdata = NULL;
+
+	memset (context->msg, 0, sizeof (context->msg));
 
 	*out = context;
 
@@ -68,6 +83,18 @@ dc_context_set_loglevel (dc_context_t *context, dc_loglevel_t loglevel)
 	return DC_STATUS_SUCCESS;
 }
 
+dc_status_t
+dc_context_set_logfunc (dc_context_t *context, dc_logfunc_t logfunc, void *userdata)
+{
+	if (context == NULL)
+		return DC_STATUS_INVALIDARGS;
+
+	context->logfunc = logfunc;
+	context->userdata = userdata;
+
+	return DC_STATUS_SUCCESS;
+}
+
 dc_status_t
 dc_context_log (dc_context_t *context, dc_loglevel_t loglevel, const char *file, unsigned int line, const char *function, const char *format, ...)
 {
@@ -79,9 +106,14 @@ dc_context_log (dc_context_t *context, dc_loglevel_t loglevel, const char *file,
 	if (loglevel > context->loglevel)
 		return DC_STATUS_SUCCESS;
 
+	if (context->logfunc == NULL)
+		return DC_STATUS_SUCCESS;
+
 	va_start (ap, format);
-	vfprintf (stderr, format, ap);
+	vsnprintf (context->msg, sizeof (context->msg), format, ap);
 	va_end (ap);
 
+	context->logfunc (context, loglevel, file, line, function, context->msg, context->userdata);
+
 	return DC_STATUS_SUCCESS;
 }
diff --git a/src/libdivecomputer.symbols b/src/libdivecomputer.symbols
index fbc599d..652c011 100644
--- a/src/libdivecomputer.symbols
+++ b/src/libdivecomputer.symbols
@@ -20,6 +20,7 @@ dc_datetime_mktime
 dc_context_new
 dc_context_free
 dc_context_set_loglevel
+dc_context_set_logfunc
 
 dc_iterator_next
 dc_iterator_free