CODEWITHSUNDEEP
c++c++11boostsegmentation-fault
DJ_
DJ_

Reputation: 247

C++ 11 Boost 1.65 recursive_directory_iterator giving segmentation fault error

My code below kept running into segmentation fault error and i can't seem to figure out why. Help pls~~ My goal is to read a folder and all of its subfolders to find all files ending with extension ".txt" so i am using boost's recurisve directory iterator to help achieve the task. This issue arrived suddenly as my code was running fine last week.

test.cpp: 

#include <sstream>
#include <iostream>
#include "/home/dj/boost_1_65_1/boost/filesystem.hpp"
using namespace std;
int main()
{
    using namespace boost::filesystem;
    recursive_directory_iterator end;
    for (recursive_directory_iterator it("./"); it != end; ++it)
    {
        std::cout << *it << endl;
    }
    return 0;
}

i am running on Linux and i compile my test.cpp with boost 1.65 as static : 

g++ -g -I /home/dj/boost_1_65_1 test.cpp -static -static-libgcc -o delete -static-libstdc++ -std=c++11 -L/home/dj/boost_1_65_1 -lboost_filesystem -lboost_system

with gdb and some cout i found that error came from the line below. 

for (recursive_directory_iterator it("./"); it != end; ++it)

somehow when i call for "recursive_directory_iterator", my system crashes giving this error

Program received signal SIGSEGV, Segmentation fault.
0x00000000004f1c8b in memcpy ()

the exact same error persists even if i reduce the code to

int main()
{
    using namespace boost::filesystem;
    recursive_directory_iterator it("./");
    return 0;
}

Upvotes: 3

Views: 970

Answers (1)

sehe
sehe

Reputation: 392893

The code is fine, the following is reduced for style:

#include <iostream>
#include <boost/filesystem.hpp>
using namespace boost::filesystem;
int main()
{
    for (recursive_directory_iterator it("./"), end; it != end; ++it) {
        std::cout << it->path() << std::endl;
    }
}

Notes:

  1. the code is incorrect for more recent versions of boost (*it is no longer output-streamable)

  2. you attempt to link to a cusomt built version of the Boost libraries in /home/dj/boost_1_65_1. However, you specify the linker directory -L/home/dj/boost_1_65_1 whereas usually the libraries get built into stage/lib so you'd expect -L/home/dj/boost_1_65_1/stage/lib to find the correct version of the libraries.

Most likely you link the wrong version of the libraries (not matching the headers you use at compile-time).

To diagnose what libraries are getting linked at runtime use ldd. For example for my example:

g++ -L /home/sehe/custom/boost_1_67_0/stage/lib/ -I /home/sehe/custom/boost_1_67_0/ test.cpp -lboost_system -lboost_filesystem

You get for ldd a.out:

    linux-vdso.so.1 =>  (0x00007fff0bfaf000)
    libboost_system.so.1.67.0 => not found
    libboost_filesystem.so.1.67.0 => not found
    libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f5e8fcb2000)
    libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f5e8fa9a000)
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f5e8f6d0000)
    libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f5e8f3c7000)
    /lib64/ld-linux-x86-64.so.2 (0x00007f5e9003e000)

Indeed, you can see I have no libboost_system.so.1.67.0 or libboost_filesystem.so.1.67.0 in a system library directory, and it won't find them. Starting would fail:

$ ./a.out 
./a.out: error while loading shared libraries: libboost_system.so.1.67.0: cannot open shared object file: No such file or directory

You can inform the runtime linker of your library path:

LD_LIBRARY_PATH=~/custom/boost_1_67_0/stage/lib ./a.out

Upvotes: 2

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