android studio cmake无法确定目标的链接器语言

我试着连接我的根 app/ 文件到C++项目,但继续得到这个错误。

CMake Error at CMakeLists.txt:15 (add_library):


    src/main/cpp/iob.c


  Tried extensions .c .C .c++ .cc .cpp .cxx .m .M .mm .h .hh .h++ .hm .hpp


  .hxx .in .txx


CMake Error: CMake can not determine linker language for target: iob

我有我的 CMakeLists.txt 文件内部 src/min/cpp 随着 iob.c 文件上写着找不到。我做错什么了?

这是我的 CMAKLISTS.TXT

# Sets the minimum version of CMake required to build your native library.
# This ensures that a certain set of CMake features is available to
# your build.

cmake_minimum_required(VERSION 3.4.1)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -Werror")

# Specifies a library name, specifies whether the library is STATIC or
# SHARED, and provides relative paths to the source code. You can
# define multiple libraries by adding multiple add.library() commands,
# and CMake builds them for you. When you build your app, Gradle
# automatically packages shared libraries with your APK.

add_library( # Specifies the name of the library.
         iob

         # Sets the library as a shared library.
         SHARED

         # Provides a relative path to your source file(s).
         src/main/cpp/iob.c )