make[1]: execvp:
/home/xxx/ncnn/android-ndk-r21b/toolchains/llvm/prebuilt/linux-x86_64/bin/clang:
Permission denied

看起来是权限问题。

make[1]: execvp:
/home/xxx/ncnn/android-ndk-r21b/toolchains/llvm/prebuilt/linux-x86_64/bin/clang:
Permission denied

看起来是权限问题。

多谢，我去试试看

make[1]: execvp:
/home/xxx/ncnn/android-ndk-r21b/toolchains/llvm/prebuilt/linux-x86_64/bin/clang:
Permission denied

看起来是权限问题。

我给clang文件增加了执行的权限，虽然Permission denied的错误消失了，但还是报同样的错。有其他办法解决吗

CMake Error at /usr/local/share/cmake-3.9/Modules/CMakeTestCCompiler.cmake:51 (message):
The C compiler
"/home/cwy/ncnn/android-ndk-r21b/toolchains/llvm/prebuilt/linux-x86_64/bin/clang"
is not able to compile a simple test program.

It fails with the following output:

Change Dir: /home/cwy/ncnn/build-android-armv7/CMakeFiles/CMakeTmp

Run Build Command:"/usr/bin/make" "cmTC_347bd/fast"

/usr/bin/make -f CMakeFiles/cmTC_347bd.dir/build.make
CMakeFiles/cmTC_347bd.dir/build

make[1]: Entering directory
'/home/cwy/ncnn/build-android-armv7/CMakeFiles/CMakeTmp'

Building C object CMakeFiles/cmTC_347bd.dir/testCCompiler.c.o

/home/cwy/ncnn/android-ndk-r21b/toolchains/llvm/prebuilt/linux-x86_64/bin/clang
--target=armv7-none-linux-androideabi24
--gcc-toolchain=/home/cwy/ncnn/android-ndk-r21b/toolchains/llvm/prebuilt/linux-x86_64
--sysroot=/home/cwy/ncnn/android-ndk-r21b/toolchains/llvm/prebuilt/linux-x86_64/sysroot
-g -DANDROID -fdata-sections -ffunction-sections -funwind-tables
-fstack-protector-strong -no-canonical-prefixes -D_FORTIFY_SOURCE=2
-march=armv7-a -mthumb -Wformat -Werror=format-security -fPIE -o
CMakeFiles/cmTC_347bd.dir/testCCompiler.c.o -c
/home/cwy/ncnn/build-android-armv7/CMakeFiles/CMakeTmp/testCCompiler.c

Linking C executable cmTC_347bd

/usr/local/bin/cmake -E cmake_link_script
CMakeFiles/cmTC_347bd.dir/link.txt --verbose=1

/home/cwy/ncnn/android-ndk-r21b/toolchains/llvm/prebuilt/linux-x86_64/bin/clang
--target=armv7-none-linux-androideabi24
--gcc-toolchain=/home/cwy/ncnn/android-ndk-r21b/toolchains/llvm/prebuilt/linux-x86_64
--sysroot=/home/cwy/ncnn/android-ndk-r21b/toolchains/llvm/prebuilt/linux-x86_64/sysroot
-g -DANDROID -fdata-sections -ffunction-sections -funwind-tables
-fstack-protector-strong -no-canonical-prefixes -D_FORTIFY_SOURCE=2
-march=armv7-a -mthumb -Wformat -Werror=format-security
-Wl,--exclude-libs,libgcc.a -Wl,--exclude-libs,libgcc_real.a
-Wl,--exclude-libs,libatomic.a -static-libstdc++ -Wl,--build-id
-Wl,--fatal-warnings -Wl,--exclude-libs,libunwind.a -Wl,--no-undefined
-Qunused-arguments -Wl,--gc-sections
CMakeFiles/cmTC_347bd.dir/testCCompiler.c.o -o cmTC_347bd -latomic -lm

/usr/bin/ld: unrecognised emulation mode: armelf_linux_eabi

Supported emulations: elf_x86_64 elf32_x86_64 elf_i386 elf_iamcu i386linux
elf_l1om elf_k1om i386pep i386pe

clang: error: linker command failed with exit code 1 (use -v to see
invocation)

CMakeFiles/cmTC_347bd.dir/build.make:97: recipe for target 'cmTC_347bd'
failed

make[1]:***[cmTC_347bd] Error 1

make[1]: Leaving directory
'/home/cwy/ncnn/build-android-armv7/CMakeFiles/CMakeTmp'

Makefile:126: recipe for target 'cmTC_347bd/fast' failed

make:***[cmTC_347bd/fast] Error 2

CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
CMakeLists.txt:25 (project)

-- Configuring incomplete, errors occurred!
See also "/home/cwy/ncnn/build-android-armv7/CMakeFiles/CMakeOutput.log".
See also "/home/cwy/ncnn/build-android-armv7/CMakeFiles/CMakeError.log".

（1）先确认下编译器能否正常使用

cmake_minimum_required(VERSION 3.6)
project(hello)
add_executable(hello   hello.cpp)

hello.cpp :

# include <iostream>

int main() {
    std::cout << "Hi" << std::endl;
    return 0;
}

编译：

mkdir build
cd build
cmake ..
make
./hello

（2）然后考虑在编译的项目的CMakeLists.txt是否正常。