I have compiled ANTLR4 runtime in a VirtualBox Ubuntu 20.04, with g++ 9.4.0.
I want to learn how to integrate the ANTLR tool into a Cpp project, So I compiled the antlr4 runtime with demo. The compilation was sucessfull, but when I try to run the built elf file. The following error occurs, the error occurs at the initialization of the Lexer. it seems that __gthread is not started.
Breakpoint 1, main () at /home/zhao/Downloads/antlr4/runtime/Cpp/demo/Linux/main.cpp:22
22 int main(int , const char **) {
(gdb) n
23 ANTLRInputStream input(u8"๐ด = ๐ + "๐";(((x * ฯ))) * ยต + โฐ; a + (x * (y ? 0 : 1) + z);");
(gdb) n
24 TLexer lexer(&input);
(gdb) s
antlrcpptest::TLexer::TLexer (this=0x7fffffffdb20, input=0x7fffffffda50) at /home/zhao/Downloads/antlr4/runtime/Cpp/demo/generated/TLexer.cpp:171
171 TLexer::TLexer(CharStream *input) : Lexer(input) {
(gdb) n
172 TLexer::initialize();
(gdb) s
antlrcpptest::TLexer::initialize () at /home/zhao/Downloads/antlr4/runtime/Cpp/demo/generated/TLexer.cpp:272
272 void TLexer::initialize() {
(gdb) s
273 std::call_once(tlexerLexerOnceFlag, tlexerLexerInitialize);
(gdb) s
std::call_once<void (&)()> (__once=..., __f=@0x7fffffffda00: {void (void)} 0x7fffffffda00) at /usr/include/c++/9/mutex:666
666 call_once(once_flag& __once, _Callable&& __f, _Args&&... __args)
(gdb) s
670 auto __callable = [&] {
(gdb)
675 __once_callable = std::__addressof(__callable); // NOLINT: PR 82481
(gdb)
std::__addressof<std::call_once<void (&)()>(std::once_flag&, void (&)())::{lambda()#1}>(void (&)()) (__r=...) at /usr/include/c++/9/bits/move.h:47
47 __addressof(_Tp& __r) _GLIBCXX_NOEXCEPT
(gdb)
48 { return __builtin_addressof(__r); }
(gdb)
std::call_once<void (&)()> (__once=..., __f=@0x55555556b4c3: {void (void)} 0x55555556b4c3 <(anonymous namespace)::tlexerLexerInitialize()>)
at /usr/include/c++/9/mutex:675
675 __once_callable = std::__addressof(__callable); // NOLINT: PR 82481
(gdb)
676 __once_call = []{ (*(decltype(__callable)*)__once_callable)(); };
(gdb)
std::call_once<void (&)()>(std::once_flag&, void (&)())::{lambda()#2}::operator void (*)()() const (this=0x7fffffffda00) at /usr/include/c++/9/mutex:676
676 __once_call = []{ (*(decltype(__callable)*)__once_callable)(); };
(gdb)
std::call_once<void (&)()> (__once=..., __f=@0x55555556b4c3: {void (void)} 0x55555556b4c3 <(anonymous namespace)::tlexerLexerInitialize()>)
at /usr/include/c++/9/mutex:683
683 int __e = __gthread_once(&__once._M_once, &__once_proxy);
(gdb)
__gthread_once (__once=0x5555556e32bc <(anonymous namespace)::tlexerLexerOnceFlag>, __func=0x7ffff7eabc20 <__once_proxy>)
at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:699
699 if (__gthread_active_p ())
(gdb) s
__gthread_active_p () at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:252
252 return __gthread_active_ptr != 0;
(gdb) display __gthread_active_ptr
1: __gthread_active_ptr = (void * const) 0x0
(gdb) n
253 }
1: __gthread_active_ptr = (void * const) 0x0
(gdb) n
__gthread_once (__once=0x5555556e32bc <(anonymous namespace)::tlexerLexerOnceFlag>, __func=0x7ffff7eabc20 <__once_proxy>)
at /usr/include/x86_64-linux-gnu/c++/9/bits/gthr-default.h:699
699 if (__gthread_active_p ())
1: __gthread_active_ptr = (void * const) 0x0
(gdb) n
702 return -1;
1: __gthread_active_ptr = (void * const) 0x0
(gdb) n
703 }
1: __gthread_active_ptr = (void * const) 0x0
(gdb) n
std::call_once<void (&)()> (__once=..., __f=@0x55555556b4c3: {void (void)} 0x55555556b4c3 <(anonymous namespace)::tlexerLexerInitialize()>)
at /usr/include/c++/9/mutex:690
690 if (__e)
1: __gthread_active_ptr = (void * const) 0x0
(gdb) n
691 __throw_system_error(__e);
I tried looking up in the CMakeLists but cannot find where the gthread package is linked. Besides, I am using a newly installed ubuntu 20.04. If it is a dependency issue please tell me which package to install.
Thank you!
Best
Zhao
2
Answers
I had the same issue when I updated the ANTLR4 version used in my project but I just added
to the
CMakeLists.txtfile of my project, whereMyTargetis the name of the library or executable where I’m linking the antlr4 library.Better explanations here and here. Hope this helps you too!
So I had this same problem and all I could find online was a suggestion to add
to the Cmake files. However, I soon realised that this solution had already been implemented as part of a patch pushed earlier in the year, but the issue was not resolved for me…
What was actually needed in my case was to set the cmake variable THREADS_PREFER_PTHREAD_FLAG to ON i.e.
set(THREADS_PREFER_PTHREAD_FLAG ON). By doing this, Cmake will pass the flag -pthread to the compiler and linker instead of -lpthread. This solved all my issues.Full breakdown to build Cpp runtime and demo with -pthread flag
Assuming you already have antlr4 installed using apt (or built manually), using the command line, go to your desired directory and clone the antlr4 repository (if you haven’t already done so):
Now generate all the lexer and parser files need for the demo as follows:
This will create multiple files and store them in demo/generated/.
From the <antlr4-dir>/runtime/Cpp directory, where <antlr4-dir> is the location you cloned the git repository, edit both CMakeLists.txt and demo/CMakeLists.txt adding
to both files and save.
Back to the command line, from location <antlr4-dir>/runtime/Cpp
the whereis command will result in the location of the antlr4 package you installed through apt (or manually installed). Lets say this location is
<apt_loc_antlr4>/antlr4, where <apt_loc_antlr4> is a location on your machine. You will need to substitute this location in the next command:Assuming all the above worked, you should now be able to run the demo.