如何解释strace输出

Question

When I execute the following program on the my embedded Linux nothing happens:

#include <boost/thread/thread.hpp>
#include <boost/lockfree/spsc_queue.hpp>
#include <iostream>

#include <boost/atomic.hpp>

void Test(void)
{
    std::cout << "Hello World" << std::endl;
}

int main(int argc, char* argv[])
{
    std::cout << "init";

    boost::thread producer_thread(Test);

    producer_thread.join();

    std::cout << "end";
}


# ./prog -> nothing happens here

The last few lines from strace output are:

open("/lib/libboost_thread.so.1.55.0", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\240\272\0\0004\0\0\0"..., 512) = 512
lseek(3, 95536, SEEK_SET)               = 95536
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1200) = 1200
lseek(3, 95226, SEEK_SET)               = 95226
read(3, "A'\0\0\0aeabi\0\1\35\0\0\0\0055T\0\6\3\10\1\t\1\22\4\24\1\25\1"..., 40) = 40
exit_group(1)                           = ?
+++ exited with 1 +++
# 

The cross compiled libbost_thread is right installed at /lib.

The program exit before main() being called. The program runs normal under my Ubuntu.

Target: ARM with buildroot (sama5d3)

Toolchain: arm-linux-gnueabihf-

Regards

Answer 1

strace is a tool that traces system calls. In your example, this consists of calls to open() , lseek() , and read() . Specifically, the snippet that you pasted shows the OS's dynamic library loader opening the libboost_thread.so.1.55.0 file and reading its contents; nothing more. It doesn't really demonstrate anything about your program except that it is linked against that library.

Answer 2

Maybe as a hint:

Have you linked against libpthread with compile and link option -pthread for your target?

If not it can have the same effect as seen in your environment: The prog starts, try to start a new thread, have no threading enabled and call the abort() function. Because abort() simply leave the prog with error in exit code nothing else happens.

Can you also add your compile & link commands for debugging purpose please!

In addition:

Your outputs without endl will not be printed because cout is buffered. The buffer will be printed only if you call flush or send a endl . Maybe you change this in your example.

Hope that helps...

Answer 3

I found the problem.

The boost library was compiled with arm-linux-gnueabi- (elibc) and the buildroot is compiled with uClibc.