c++ - 我尝试使用 cmake 来制作项目，但它调用了一个错误 ld: library not found for -levmc::loader

Question

我 git 克隆了一个名为 evmc 的项目在 github 上。

我尝试通过 cmake 在这个项目中构建 example 文件夹。但是这里有一些错误叫做:

使用 cmake .

-- Configuring done
CMake Error at CMakeLists.txt:23 (add_executable):
  Target "evmc-example" links to target "evmc::evmc_cpp" but the target was
  not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?


CMake Error at CMakeLists.txt:23 (add_executable):
  Target "evmc-example" links to target "evmc::loader" but the target was not
  found.  Perhaps a find_package() call is missing for an IMPORTED target, or
  an ALIAS target is missing?


CMake Error at CMakeLists.txt:19 (add_executable):
  Target "evmc-example-static" links to target "evmc::evmc_cpp" but the
  target was not found.  Perhaps a find_package() call is missing for an
  IMPORTED target, or an ALIAS target is missing?


CMake Error at CMakeLists.txt:19 (add_executable):
  Target "evmc-example-static" links to target "evmc::evmc" but the target
  was not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?


CMake Error at CMakeLists.txt:19 (add_executable):
  Target "evmc-example-static" links to target "evmc::evmc" but the target
  was not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?


CMake Error at CMakeLists.txt:16 (add_library):
  Target "evmc-example-host" links to target "evmc::evmc_cpp" but the target
  was not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?


CMake Error at example_vm/CMakeLists.txt:10 (add_library):
  Target "example-vm-static" links to target "evmc::evmc" but the target was
  not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?


CMake Error at example_vm/CMakeLists.txt:5 (add_library):
  Target "example-vm" links to target "evmc::evmc" but the target was not
  found.  Perhaps a find_package() call is missing for an IMPORTED target, or
  an ALIAS target is missing?


CMake Error at example_precompiles_vm/CMakeLists.txt:10 (add_library):
  Target "example-precompiles-vm-static" links to target "evmc::evmc" but the
  target was not found.  Perhaps a find_package() call is missing for an
  IMPORTED target, or an ALIAS target is missing?


CMake Error at example_precompiles_vm/CMakeLists.txt:5 (add_library):
  Target "example-precompiles-vm" links to target "evmc::evmc" but the target
  was not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?


-- Generating done
CMake Generate step failed.  Build files cannot be regenerated correctly.
make: *** [cmake_check_build_system] Error 1

使用make

Consolidate compiler generated dependencies of target evmc-example-host
[ 14%] Built target evmc-example-host
Consolidate compiler generated dependencies of target evmc-example
[ 21%] Linking CXX executable evmc-example
ld: library not found for -levmc::loader
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [evmc-example] Error 1
make[1]: *** [CMakeFiles/evmc-example.dir/all] Error 2
make: *** [all] Error 2

这是我的 CMakeLists:

# EVMC: Ethereum Client-VM Connector API.
# Copyright 2016-2019 The EVMC Authors.
# Licensed under the Apache License, Version 2.0.

cmake_minimum_required(VERSION 3.13)

set (CMAKE_C_COMPILER /usr/bin/clang)
set (CMAKE_CXX_COMPILER /usr/bin/clang++)
set (CMAKE_CXX_STANDARD 17)

include(GNUInstallDirs)

add_subdirectory(example_vm)
add_subdirectory(example_precompiles_vm)

add_library(evmc-example-host STATIC example_host.cpp)
target_link_libraries(evmc-example-host PRIVATE evmc::evmc_cpp)

add_executable(evmc-example-static example.c)
target_link_libraries(evmc-example-static PRIVATE evmc-example-host evmc::example-vm-static evmc::evmc)
target_compile_definitions(evmc-example-static PRIVATE STATICALLY_LINKED_EXAMPLE)

add_executable(evmc-example example.c)
target_link_libraries(evmc-example PRIVATE evmc-example-host evmc::loader)

include_directories(../include)

这是我的项目结构:

evmc
├── AUTHORS.md
├── CHANGELOG.md
├── CMakeCache.txt
├── CMakeLists.txt
├── CNAME
├── CPackConfig.cmake
├── CPackSourceConfig.cmake
├── Cargo.lock
├── Cargo.toml
├── Doxyfile
├── LICENSE
├── Makefile
├── README.md
├── appveyor.yml
├── bindings
│   ├── go
│   ├── java
│   └── rust
├── build
│   ├── CMakeCache.txt
│   ├── CMakeFiles
│   ├── CPackConfig.cmake
│   ├── CPackSourceConfig.cmake
│   ├── Makefile
│   ├── cmake_install.cmake
│   ├── evmcConfig.cmake
│   ├── evmcConfigVersion.cmake
│   └── lib
├── circle.yml
├── cmake
│   ├── Config.cmake.in
│   ├── EVMC.cmake
│   ├── Hunter
│   └── cable
├── cmake_install.cmake
├── codecov.yml
├── docs
│   ├── EVMC.md
│   ├── Host_Guide.md
│   ├── VM_Guide.md
│   ├── VM_Tester.md
│   └── custom.dox
├── evmcConfig.cmake
├── evmcConfigVersion.cmake
├── examples
│   ├── CMakeCache.txt
│   ├── CMakeFiles
│   ├── CMakeLists.txt
│   ├── Makefile
│   ├── build
│   ├── cmake_install.cmake
│   ├── example-rust-vm
│   ├── example.c
│   ├── example_host.cpp
│   ├── example_host.h
│   ├── example_precompiles_vm
│   ├── example_vm
│   ├── libevmc-example-host.a
│   ├── use_evmc_in_cmake
│   └── use_instructions_in_cmake
├── go.mod
├── include
│   └── evmc
├── lib
│   ├── CMakeFiles
│   ├── CMakeLists.txt
│   ├── Makefile
│   ├── cmake_install.cmake
│   ├── hex
│   ├── instructions
│   ├── loader
│   └── mocked_host
├── target
│   ├── CACHEDIR.TAG
│   └── debug
├── test
│   ├── CMakeLists.txt
│   ├── cmake_package
│   ├── compilation
│   ├── examples
│   ├── gomod
│   ├── tools
│   ├── unittests
│   └── vmtester
└── tools
    ├── CMakeLists.txt
    ├── commands
    ├── evmc
    ├── utils
    └── vmtester

我已经升级了我在这个项目中使用的所有工具:clang、cmake...

但是还是不能正常运行，怎么办？

Answer 1

这发生在我身上是因为我用于库的路径不正确，它没有指向包含 CMakeLists.txt 的目录。

我在我的顶级 CMakeLists.txt 中使用 FetchContent 包含 cpr，并意外地将 FETCHCONTENT_SOURCEDIR_CPR 设置为上面的级别。我在 cpr/cpr-master 中有 cpr 的源代码，但只是将它设置为 cpr。

更笼统地回答，这意味着 evmc 的路径可能不正确。