error while loading shared libraries: libtre.so.5: cannot open shared object file: No such file or directory

[nyangz]

Hi there, thanks for this amazing library. I am used to work with third-party APIs that expose TRE, but for the first time I will need to use it directly from within C++.

So, here is what I did. I downloaded a copy of the repository and followed the build instructions:

./configure
make
make check

At that point, all checks seemed to work without any errors until the agrep test stage, where only one test is passed - all the rest fail. In the test log, I see many many identical errors:

error while loading shared libraries: libtre.so.5: cannot open shared object file: No such file or directory

For the purpose of further testing, I then continued:

make install

Everything else seems to proceed wit no additional errors. Next, I tried to compile a small test code from a file called test.cpp, located in the root folder, that contains merely:

extern "C" {
#include "tre/lib/tre.h"
}

int main()
{
    regex_t tgt;
    tre_regcomp(&tgt, "First Try", REG_EXTENDED);

    return 0;
}

When I compile with g++ test.cpp -ltre, still no error thrown. However, when I then try ./a.out, I get the error:

./a.out: error while loading shared libraries: libtre.so.5: cannot open shared object file: No such file or directory

How could I solve such issues?

[cben]

Some tips:

• ldd ./a.out will should you what libraries files the binary requires. But this will probably say libtre.so.5, duh, not too helpful here.
• find -name '*.so*'. For me this prints:

  ./lib/.libs/libtre.so.5
  ./lib/.libs/libtre.so.5.0.0
  ./lib/.libs/libtre.so
  

• Your final g++ test.cpp -ltre assumes it got installed in the standard system locations. Did make install actually put it there? Default prefix should put it at /usr/local/lib/libtre.so.5.0.0. Maybe you needed sudo make install (though it should have failed if permissions are the issue).
• Look at output of make check (maybe make clean; make first) for compilation commands, what it's linking to. Specifically, search for libtre. For me, it links to ../lib/.libs/libtre.so:

  libtool: link: gcc -g -O2 -Wall -o .libs/test-str-source test-str-source.o  ../lib/.libs/libtre.so -lm -Wl,-rpath -Wl,/usr/local/lib
  

However, if I rm lib/.libs/libtre.so*, then make check fails with same error as you wrote (in tests/agrep/test-suite.log). And then, even make && make check doesn't help, the lib is not re-built. => So maybe your dir is stuck in some broken state. Try make clean; make; make check.