6

The error

I am trying to use std::thread but I have this error when I try to run it.

terminate called after throwing an instance of 'std::system_error'

what(): Enable multithreading to use std::thread: Operation not permitted

Aborted (core dumped)

Result of my research

There are a lot of questions about it and every answer say similar things : I have to build with "-pthread" or "-lpthread". Some also say to add "-Wl,--no-as-needed".

Link Link Link Link Link Link Link

I tried a lot of things but none worked.

Details

I am compiling with Code::Blocks 12.11, GNU GCC Compiler on Lubuntu. In the compiler settings menu, compiler flags I have checked

"Have g++ follow the C++11 ISO C++ language standard [-std=c++11]"

and under other options I wrote what the answer was saying, here is an example

-pthread
-Wl,--no-as-needed

Here is the build log I have (I am not sure if it is important)

g++ -Wall -fexceptions  -std=c++11 -g -pthread -Wl,--no-as-needed  -std=c++11   -I../DeskManagerDll -I/usr/include/X11/extensions -I/usr/include/X11  -c /home/julien/Documents/test/main.cpp -o obj/Debug/main.o
g++ -L/home/julien/Documents/DeskManagerDll -L-L/usr/lib/i386-linux-gnu  -o bin/Debug/test obj/Debug/main.o   -L/usr/X11R6/lib  -lX11 -lXext -lpthread -Wl,--no-as-needed  /home/julien/Documents/DeskManagerDll/bin/Debug/libDeskManagerDll.so 
Output size is 187,15 KB

My question

What am I doing wrong ? What did I miss ?

Edit

I made a very simple program to exclude any other problem.

#include <thread>

void test()
{
    
}

int main()
{
    std::thread thread_fct (test);
    return 0;
}

The build log with this program:

g++ -Wall -fexceptions  -std=c++11 -g -pthread -Wl,--no-as-needed  -std=c++11    -c /home/julien/Documents/test/main.cpp -o obj/Debug/main.o
g++  -o bin/Debug/test obj/Debug/main.o

I still have the exact same error. I really don't know what to try. Do you have any idea ?

Community
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Heckel
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    Try adding `-pthread` to the `.so` compilation as well. – juanchopanza May 15 '14 at 12:05
  • I don't see how to do that, do you know what I should google to find where I can modify it ? I am a bit lost in all of this – Heckel May 15 '14 at 12:14
  • In your second `g++` line, add `-pthread` (and possibly remove `-lpthread`, `-pthread` should do that for you.) – juanchopanza May 15 '14 at 12:15
  • It has been automaticaly generated by code::blocks. I can modify it through the options but the "other option" field changes the first line. – Heckel May 15 '14 at 12:17
  • IMO it's a bit unexpected for the standard library to start overloading `EPERM` to mean something pretty different. – Brian Cain May 16 '14 at 13:02
  • I am sorry, I don't understand what you mean. Is it the error or my compiler settings that are unexpected ? – Heckel May 16 '14 at 13:15

2 Answers2

6

Your first problem is that -lpthread is a linker option, so it belongs on the linker line (the second command) rather than the compilation line. (Note that the order of the parameters can matter; I got it to work by putting -lpthread on last. I also tried using -pthread instead of -lpthread, which did appear to work and was also less sensitive to where it was put on the linker line. But again, it's a linker option, not a compile option.)

After fixing that, I was able to get your program to compile and run, but it exited with a different exception: terminate called without an active exception. To fix this problem, call thread_fct.join(); in main(). (All threads must be joined, detached, or moved-from before they go out of scope, or your program will abort.)

Adam H. Peterson
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2

The way that was useful for me for code::blocks:

  1. Project -> Build options -> Have g++ follow C++11 ISO ... [-std=c+11] (select checkbox)

  2. Project -> Build options -> Linker settings -> Other linker options add there

    -Wl,--no-as-needed
-pthread
Willi Mentzel
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Alexey Wodka
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