diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1e41be6..af175f4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,7 +16,7 @@ if(GIT_EXECUTABLE)
   if(NOT GIT_DESCRIBE_ERROR_CODE)
       string(SUBSTRING ${GIT_DESCRIBE_VERSION} 0 1 VIMIX_VERSION_MAJOR)
       string(SUBSTRING ${GIT_DESCRIBE_VERSION} 2 1 VIMIX_VERSION_MINOR)
-      string(LENGTH ${GIT_DESCRIBE_VERSION} VIMIX_VERSION_LENGTH)
+      string(FIND ${GIT_DESCRIBE_VERSION} "-" VIMIX_VERSION_LENGTH)
       if (VIMIX_VERSION_LENGTH GREATER 4)
           string(SUBSTRING ${GIT_DESCRIBE_VERSION} 4 1 VIMIX_VERSION_PATCH)
       else()