diff --git a/CMakeLists.txt b/CMakeLists.txt
index abf2c0b8..d545ff00 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -36,6 +36,7 @@ if(USE_GCOV)
   SET(GCC_COVERAGE_COMPILE_FLAGS "-fprofile-arcs -ftest-coverage")
   SET(GCC_COVERAGE_LINK_FLAGS "-lgcov")
   SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${GCC_COVERAGE_COMPILE_FLAGS}")
+  SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${GCC_COVERAGE_COMPILE_FLAGS}")
   SET(CMAKE_EXE_LINKER_FLAGS "${CMAKE_LINKER_FLAGS} ${GCC_COVERAGE_LINK_FLAGS}")
 endif(USE_GCOV)
 
diff --git a/tests/README.md b/tests/README.md
index 5f5619a8..87fedecf 100644
--- a/tests/README.md
+++ b/tests/README.md
@@ -16,7 +16,7 @@ Generate image files .gcno and data files .gcda under build/tests/CMakeFiles/.di
 Execute the following command in the build folder to generate an intermediate file for HTML:
 
 ```shell
-$ lcov --capture --directory . -- output-file testneuron.info --test-name testneuron
+$ lcov --capture --directory . --output-file testneuron.info --test-name testneuron
 ```
 
 Execute the following command in the build folder to generate an HTML file in the result folder under the build folder: