diff --git a/cmake/scripts/SquirrelExport.cmake b/cmake/scripts/SquirrelExport.cmake
--- a/cmake/scripts/SquirrelExport.cmake
+++ b/cmake/scripts/SquirrelExport.cmake
@@ -71,13 +71,23 @@ reset_reader()
 
 file(STRINGS "${SCRIPT_API_FILE}" SOURCE_LINES)
 
+set(NUM_LINE 0)
+macro(doxygen_check)
+    if(NOT "${DOXYGEN_SKIP}" STREQUAL "")
+        message(FATAL_ERROR "${SCRIPT_API_FILE}:${NUM_LINE}: a DOXYGEN_API block was not properly closed")
+    endif()
+endmacro()
+
 foreach(LINE IN LISTS SOURCE_LINES)
+    math(EXPR NUM_LINE "${NUM_LINE} + 1")
     # Ignore special doxygen blocks
     if("${LINE}" MATCHES "^#ifndef DOXYGEN_API")
+        doxygen_check()
         set(DOXYGEN_SKIP "next")
         continue()
     endif()
     if("${LINE}" MATCHES "^#ifdef DOXYGEN_API")
+        doxygen_check()
         set(DOXYGEN_SKIP "true")
         continue()
     endif()
@@ -86,10 +96,10 @@ foreach(LINE IN LISTS SOURCE_LINES)
         continue()
     endif()
     if("${LINE}" MATCHES "^#else")
-        if("${DOXYGEN_SKIP}" STREQUAL "next")
+        if(DOXYGEN_SKIP STREQUAL "next")
             set(DOXYGEN_SKIP "true")
-        else()
-            unset(DOXYGEN_SKIP)
+        elseif(DOXYGEN_SKIP STREQUAL "true")
+            set(DOXYGEN_SKIP "false")
         endif()
         continue()
     endif()
@@ -668,4 +678,6 @@ foreach(LINE IN LISTS SOURCE_LINES)
     endif()
 endforeach()
 
+doxygen_check()
+
 configure_file(${SCRIPT_API_SOURCE_FILE} ${SCRIPT_API_BINARY_FILE})