diff --git a/CMakeLists.txt b/CMakeLists.txt
index a59d256..a82620a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,26 +10,22 @@
 #   Print all options: cmake -LAH ..
 #
 
-
 ## CMake settings
 cmake_minimum_required (VERSION 3.5.1) # Need >= 3.8 for first-class CUDA support
 
 ## Project settings
 project(astaroth C CXX)
-set(CMAKE_CXX_STANDARD 11)
-set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR})
 
 ## Options
 option(BUILD_DEBUG              "Builds the program with extensive error checking"          OFF)
 option(BUILD_STANDALONE         "Builds the standalone Astaroth"                            ON)
 option(BUILD_RT_VISUALIZATION   "Builds the module for real-time visualization using SDL2"  OFF)
+option(BUILD_C_API_TEST         "Builds a C program to test whether the API is conformant"  ON)
 option(DOUBLE_PRECISION         "Generates double precision code"                           OFF)
 option(MULTIGPU_ENABLED         "If enabled, uses all the available GPUs"                   ON)
 option(ALTER_CONF               "If enabled, loads astaroth.conf from the build directory"  OFF)
 
-
-
 ## Build types
 # Available types (case-sensitive):
 # RELEASE         (best performance)
@@ -41,27 +37,24 @@ else ()
 endif()
 message(STATUS "Build type: " ${CMAKE_BUILD_TYPE})
 
-
 ## Defines
 if (DOUBLE_PRECISION)
     add_definitions(-DAC_DOUBLE_PRECISION=1)
 else ()
     add_definitions(-DAC_DOUBLE_PRECISION=0)
 endif ()
-if (MULTIGPU_ENABLED)
-    add_definitions(-DAC_MULTIGPU_ENABLED=1)
-else ()
-    add_definitions(-DAC_MULTIGPU_ENABLED=0)
-endif ()
 
 ## Include directories
 include_directories(.)
 include_directories(include)
 
 ## Subdirectories
-add_subdirectory(src/core)
+add_subdirectory(src/core) # The core library
+
 if (BUILD_STANDALONE)
     add_subdirectory(src/standalone)
 endif ()
 
-add_subdirectory(src/ctest)
+if (BUILD_C_API_TEST)
+    add_subdirectory(src/ctest)
+endif ()
diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index e70de80..5cbc271 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -25,6 +25,13 @@ set(CUDA_NVCC_FLAGS ${CUDA_NVCC_FLAGS} ${CUDA_ARCH_FLAGS} ${CUDA_WARNING_FLAGS})
 set(CUDA_NVCC_FLAGS_RELEASE)
 set(CUDA_NVCC_FLAGS_DEBUG --device-debug --generate-line-info --ptxas-options=-v)
 
+## Definitions
+if (MULTIGPU_ENABLED)
+    add_definitions(-DAC_MULTIGPU_ENABLED=1)
+else ()
+    add_definitions(-DAC_MULTIGPU_ENABLED=0)
+endif ()
+
 ## Create and link the library
 include_directories(.)
 cuda_add_library(astaroth_core STATIC astaroth.cu device.cu)
diff --git a/src/ctest/CMakeLists.txt b/src/ctest/CMakeLists.txt
index 393d7b6..f3439f3 100644
--- a/src/ctest/CMakeLists.txt
+++ b/src/ctest/CMakeLists.txt
@@ -1,2 +1,9 @@
+##############################################
+##  CMakeLists.txt for the C API test       ##
+##############################################
+
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_C_STANDARD_REQUIRED ON)
+
 add_executable(ctest main.c)
 target_link_libraries(ctest PRIVATE astaroth_core)
diff --git a/src/ctest/README.txt b/src/ctest/README.txt
new file mode 100644
index 0000000..68750d2
--- /dev/null
+++ b/src/ctest/README.txt
@@ -0,0 +1 @@
+This directory is used to test whether the Astaroth API is compatible with C.
diff --git a/src/standalone/CMakeLists.txt b/src/standalone/CMakeLists.txt
index 9ca17e5..b444800 100644
--- a/src/standalone/CMakeLists.txt
+++ b/src/standalone/CMakeLists.txt
@@ -2,6 +2,9 @@
 ##  CMakeLists.txt for Astaroth Standalone  ##
 ##############################################
 
+set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
 ## Files
 file (GLOB SOURCES "*.cc" "model/*.cc")
 
@@ -17,7 +20,6 @@ if (BUILD_RT_VISUALIZATION)
     link_directories(${SDL2_LIBRARY_DIR})
 endif ()
 
-
 ## Compilation flags
 add_compile_options(-march=native -pipe ${OpenMP_CXX_FLAGS})
 add_compile_options(-Wall -Wextra -Werror -Wdouble-promotion -Wfloat-conversion)# -Wshadow)