Cannot compile example_trivial.cpp in Linux

[hungptit]

I try to compile example_trivial.cpp in Linux using clang++-9.0.1 and get below compilation errors. Do you have any suggestion?

Thanks,
Hung

[ 50%] Building CXX object CMakeFiles/test_quill.dir/test_quill.cpp.o                                                                                                                                                                 
In file included from /home/hungptit/working/cppidioms/src/test_quill.cpp:1:                                                                                                                                                          
In file included from /home/hungptit/working/cppidioms/src/../3p/include/quill/Quill.h:8:                                                                                                                                             
/home/hungptit/working/cppidioms/src/../3p/include/quill/detail/LogMacros.h:39:62: error: token pasting of ',' and                                                                                                                    
      __VA_ARGS__ is a GNU extension [-Werror,-Wgnu-zero-variadic-macro-arguments]                                                                                                                                                    
    QUILL_LOGGER_CALL(logger, quill::LogLevel::TraceL3, fmt, ##__VA_ARGS__)                                                                                                                                                           
                                                             ^                                                                                                                                                                        
/home/hungptit/working/cppidioms/src/../3p/include/quill/detail/LogMacros.h:33:54: error: token pasting of ',' and                                                                                                                    
      __VA_ARGS__ is a GNU extension [-Werror,-Wgnu-zero-variadic-macro-arguments]                                                                                                                                                    
    logger->log<log_statement_level>(&log_line_info, ##__VA_ARGS__)...                                                                                                                                                                
                                                     ^                                                                                                                                                                                
/home/hungptit/working/cppidioms/src/../3p/include/quill/detail/LogMacros.h:46:62: error: token pasting of ',' and                                                                                                                    
      __VA_ARGS__ is a GNU extension [-Werror,-Wgnu-zero-variadic-macro-arguments]                                                                                                                                                    
    QUILL_LOGGER_CALL(logger, quill::LogLevel::TraceL2, fmt, ##__VA_ARGS__)                                                                                                                                                           
                                                             ^                                                                                                                                                                        
/home/hungptit/working/cppidioms/src/../3p/include/quill/detail/LogMacros.h:33:54: error: token pasting of ',' and                                                                                                                    
      __VA_ARGS__ is a GNU extension [-Werror,-Wgnu-zero-variadic-macro-arguments]                                                                                                                                                    
    logger->log<log_statement_level>(&log_line_info, ##__VA_ARGS__)...                                                              

And this is the compilation command

{                                                                                                                                                                                                                                     
  "directory": "/home/hungptit/working/cppidioms/src",                                                                                                                                                                                
  "command": "clang++   -I/home/hungptit/working/cppidioms/src/../3p/include -I/home/hungptit/working/cppidioms/src/../src    -O3  -march=native  -std=c++17  -Wall  -pedantic  -pedantic-errors  -fstrict-aliasing  -Wstrict-aliasing  -DFMT_HEADER_ONLY  -DCEREAL_RAPIDJSON_HAS_CXX11_RVALUE_REFS  -flto  -static -O3 -DNDEBUG   -o CMakeFiles/test_quill.dir/test_quill.cpp.o -c /home/hungptit/working/cppidioms/src/test_quill.cpp",                                  
  "file": "/home/hungptit/working/cppidioms/src/test_quill.cpp"                                                                                                                                                                       
},

[odygrd]

Hello, thanks for reporting.

I am unable to reproduce on Ubuntu using clang++9,0 and the following compilation flags :

-O3 -march=native -std=c++17 -Wall -pedantic -pedantic-errors -fstrict-aliasing -Wstrict-aliasing -static -DNDEBUG -std=gnu++17

clang version 9.0.0-2 (tags/RELEASE_900/final)

It looks related to this hamon-in/cpslib#30

Could you please :

1. Double check you are using clang++9.1. Please do run clang++ --version on a terminal
2. In your compilation command above use clang++-9.1 instead of clang++
3. Remove -pedantic -pedantic-errors from your compilation command if step 2 does not work and try again

[hungptit]

Hi,

I can compile above example after removing -pedantic and -pedantic-errors flags, however, the compiled binary give me a segv. You can find my build configuration here https://github.com/hungptit/cppidioms/blob/test_quill/src/test_quill.cpp. I take a quick look at the issue using gdb and the error seem to be related to thread

(gdb) run
Starting program: /home/hungptit/working/cppidioms/src/test_quill 
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
[New Thread 0x7ffff7ffa700 (LWP 5916)]

Thread 1 "test_quill" received signal SIGSEGV, Segmentation fault.
0x0000000000000000 in ?? ()
(gdb) up
#1  0x00000000004e0e33 in std::thread::join() ()
(gdb) up
#2  0x0000000000403e79 in quill::detail::BackendWorker::stop() ()
(gdb) up
#3  0x0000000000402f77 in quill::detail::LogManagerSingleton::~LogManagerSingleton() ()
(gdb) up
#4  0x0000000000524ab8 in __run_exit_handlers ()
(gdb) up
#5  0x0000000000524caa in exit ()
(gdb) up
#6  0x0000000000511bec in __libc_start_main ()
(gdb) up
#7  0x000000000041edea in _start ()
(gdb) up
Initial frame selected; you cannot go up.

[odygrd]

thanks, what linux distro are you using ? And how did you install clang 9.0 ? I would like to recreate the os image you are using to see if I can reproduce

[hungptit]

I use Gentoo and I get segv using both gcc and clang++. Below is the detail information

~ $ gcc --version                                                                                                                                                                                                                     
gcc (Gentoo 9.3.0 p1) 9.3.0                                                                                                                                                                                                           
Copyright (C) 2019 Free Software Foundation, Inc.                                                                                                                                                                                     
This is free software; see the source for copying conditions.  There is NO                                                                                                                                                            
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.                                                                                                                                                           
                                                                                                                                                                                                                                      
~ $ clang++ --version                                                                                                                                                                                                                 
clang version 9.0.1                                                                                                                                                                                                                   
Target: x86_64-pc-linux-gnu                                                                                                                                                                                                           
Thread model: posix                                                                                                                                                                                                                   
InstalledDir: /usr/lib/llvm/9/bin        

I take another quick look at the problem and I find out that -static flag is the main problem. Can you check if test_quill does not depend on any library when compiling with -static flag in your Ubuntu machine?

Compiled without -static flag

~/working/cppidioms/src $ ldd ./test_quill                                                                                                                                                                                            
        linux-vdso.so.1 (0x00007fff719be000)                                                                                                                                                                                          
        libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f2b2e26f000)                                                                                                                                                                
        libstdc++.so.6 => /usr/lib/gcc/x86_64-pc-linux-gnu/9.3.0/libstdc++.so.6 (0x00007f2b2dff1000)                                                                                                                                  
        libm.so.6 => /lib64/libm.so.6 (0x00007f2b2deb7000)                                                                                                                                                                            
        libgcc_s.so.1 => /usr/lib/gcc/x86_64-pc-linux-gnu/9.3.0/libgcc_s.so.1 (0x00007f2b2de9d000)                                                                                                                                    
        libc.so.6 => /lib64/libc.so.6 (0x00007f2b2dcde000)                                                                                                                                                                            
        /lib64/ld-linux-x86-64.so.2 (0x00007f2b2e32e000)                                                                                                                                                                              

Compiled using -static flag

~/working/cppidioms/src $ ldd ./test_quill                                                                                                                                                                                            
        not a dynamic executable    

[odygrd]

Hello, thanks for looking into it.

I managed to reproduce the clang va_args error and the -static error

The library is using std::thread to spawn a backend logging thread and on linux std::thread depends on pthread which is usually linked dynamically.

Using gcc 9 or clang9 - The behaviour is similar :

• I get the same segfault as you when using '-static'. This looks related to this. I was able to run without segfault using the compilation flags :
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -static -Wl,--whole-archive -lpthread -Wl,--no-whole-archive")

• The example runs okay and those extra compilation flags are not needed when i remove -static

Can you try using the above compilation flags and let me know if it works ?

Also does it run okay for you without segfault with clang9 when you remove -static -pedantic -pedantic-errors ?

Also, the library sets it's own compiler flags for the library target only in cmake

If you want to compile the example and still use -static for the example not the library I would recommend using something like this rather than passing the arguments globally :

add_executable(example_trivial example_trivial.cpp)
target_link_libraries(example_trivial quill)
target_compile_options(example_trivial PRIVATE -static)

This would compile only the target example_trivial with -static but still quill library will be built without -static

[hungptit]

I think my problem will go away if quill can be used in header only build. Do you plan to support header only build?

[odygrd]

as mentioned here it will require many changes for this.

can you try adding -static -Wl,--whole-archive -lpthread -Wl,--no-whole-archive to your compilation flags and let me know if it goes away ?

[hungptit]

I confirm that the problem is go away if I use above linking options, however, the output of ldd shows that the final binary do depend on my system dynamic libraries. I will try quill again when the header only build is supported.

Thank a lot for your help.
Hung

 ~/working/cppidioms/src $ ldd ./test_quill
        linux-vdso.so.1 (0x00007ffcd7ff9000)
        libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f34b5869000)
        libstdc++.so.6 => /usr/lib/gcc/x86_64-pc-linux-gnu/9.3.0/libstdc++.so.6 (0x00007f34b55eb000)
        libm.so.6 => /lib64/libm.so.6 (0x00007f34b54b1000)
        libgcc_s.so.1 => /usr/lib/gcc/x86_64-pc-linux-gnu/9.3.0/libgcc_s.so.1 (0x00007f34b5497000)
        libc.so.6 => /lib64/libc.so.6 (0x00007f34b52d8000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f34b58cd000). 

[hungptit]

BTW, I really like quill and I look forward to try it out in the near future. My use cases is quite special because my binaries need to run on different Linux machines.