CMake函数“未在此范围内声明”错误

问题描述

我是CMake的新手，并且一直在阅读博客以使它生效。当所有文件都在同一个目录中时，我有一个cmake文件正在工作，但似乎无法正常工作-包含目录给我带来了麻烦。在这最后一次尝试中，我引用了this堆栈溢出线程。这是我最近一次使它起作用。请帮忙。

文件树

$ tree
.
├── CMakeLists.txt
├── include
│   ├── CMakeLists.txt
│   └── math.h
├── src
│   ├── CMakeLists.txt
│   └── math.c
└── testy
    ├── CMakeLists.txt
    └── math.cpp

3 directories,7 files

CMake文件

$ more CMakeLists.txt
cmake_minimum_required(VERSION 3.1)
project(iamtesting)
enable_testing()
add_subdirectory(include)
add_subdirectory(src)
add_subdirectory(testy)

$ more include/CMakeLists.txt
add_library(include INTERFACE)
target_include_directories(include INTERFACE ./)

$ more src/CMakeLists.txt
add_library(src STATIC math.c)
target_include_directories(src PUBLIC ./)

$ more testy/CMakeLists.txt
set(TEST_EXE_NAME math)
add_executable(${TEST_EXE_NAME} math.cpp)
target_include_directories(${TEST_EXE_NAME} PUBLIC ./)
target_link_libraries(${TEST_EXE_NAME} src)
add_test(NAME "testDatabase" COMMAND ${TEST_EXE_NAME})

CMake

$ cmake CMakeLists.txt
-- The C compiler identification is GNU 7.5.0
-- The CXX compiler identification is GNU 7.5.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Configuring done
-- Generating done
-- Build files have been written to: /home/jason/gtest

制作

$ make
Scanning dependencies of target src
[ 25%] Building C object src/CMakeFiles/src.dir/math.c.o
/home/jason/gtest/src/math.c: In function ‘main’:
/home/jason/gtest/src/math.c:5:24: warning: implicit declaration of function ‘sum’ [-Wimplicit-function-declaration]
   printf("10+20=%d\n",sum(10,20));
                        ^~~
[ 50%] Linking C static library libsrc.a
[ 50%] Built target src
Scanning dependencies of target math
[ 75%] Building CXX object testy/CMakeFiles/math.dir/math.cpp.o
In file included from /usr/include/gtest/gtest.h:1874:0,from /home/jason/gtest/testy/math.cpp:1:
/home/jason/gtest/testy/math.cpp: In member function ‘virtual void widget_ok_Test::TestBody()’:
/home/jason/gtest/testy/math.cpp:5:13: error: ‘sum’ was not declared in this scope
   ASSERT_EQ(sum(1,1),2);
             ^
/home/jason/gtest/testy/math.cpp:5:3: error: template argument 1 is invalid
   ASSERT_EQ(sum(1,2);
   ^
testy/CMakeFiles/math.dir/build.make:62: recipe for target 'testy/CMakeFiles/math.dir/math.cpp.o' Failed
make[2]: *** [testy/CMakeFiles/math.dir/math.cpp.o] Error 1
CMakeFiles/Makefile2:158: recipe for target 'testy/CMakeFiles/math.dir/all' Failed
make[1]: *** [testy/CMakeFiles/math.dir/all] Error 2
Makefile:94: recipe for target 'all' Failed
make: *** [all] Error 2

Src文件

$ more src/math.c
#include <stdio.h>
#include "math.h"

int main() {
  printf("10+20=%d\n",20));
  return 0;
}

int sum(int x,int y) {
    return x + y;
}

$ more include/math.h
#define _MATH_H_

int sum(int,int);

$ more src/math.c
#include <stdio.h>
#include "math.h"

int main() {
  printf("10+20=%d\n",int y) {
    return x + y;
}

$ more testy/math.cpp
#include "gtest/gtest.h"
#include "math.h"

TEST(widget,ok) {
  ASSERT_EQ(sum(1,2);
}

int main(int argc,char **argv) {
    testing::InitGoogleTest(&argc,argv);
    return RUN_ALL_TESTS();
}

解决方法

您的设置存在很多问题：

libInclude（在include/CMakeLists.txt中定义）。您需要创建一个库libSrc，该库具有通过include添加的target_include_directories目录。
src文件夹不应通过target_include_directories添加，因为它仅存储实现您功能的源文件，并且在任何地方都绝不能用作#include。
每个程序中只能有一个main函数，因此很可能应该从main中删除src/math.c。您的可执行文件应该有一个main.cpp，它会链接libSrc，测试中应该有一个main方法（对于您的情况，math.cpp，您正在链接{{1} }正确地存在）
libSrc应具有正确的include guard

cmake googletest