Boost link error when using “--layout=system” on V

问题:

I'm new to boost, and thought I'd try it out with some realistic deployment scenarios for the .dlls, so I used the following command to compile/install the libraries:

.\bjam install --layout=system variant=debug runtime-link=shared link=shared
--with-date_time --with-thread --with-regex --with-filesystem
--includedir=<my include directory> --libdir=<my bin directory> > installlog.txt

That seemed to work, but my simple program (taken right from the "Getting Started" page) fails:

#include <boost/regex.hpp>
#include <iostream>
#include <string>

// Place your functions after this line
int main()
{
    std::string line;
    boost::regex pat( "^Subject: (Re: |Aw: )*(.*)" );

    while (std::cin)
    {
        std::getline(std::cin, line);
        boost::smatch matches;
        if (boost::regex_match(line, matches, pat))
            std::cout << matches[2] << std::endl;
    }
}

This fails with the following linker error:

fatal error LNK1104: cannot open file 'libboost_regex-vc80-mt-1_42.lib'

I'm sure that both the .lib and the .dlls are in that directory, and named how I want them to be (ie: boost_regex.lib, etc, all unversioned, as the --layout=system says). So why is it looking for the versioned type of it? And how do I get it to look for the unversioned type of the library?

I've tried this with more "normal" options, such as below:

.\bjam stage --build-type=complete --with-date_time --with-thread --with-filesystem --with-regex > mybuildlog.txt

And that works fine. I made sure my compiler saw the "stage\lib" directory, and it compiled and ran fine with nothing beyond having the environment looking into the right lib directory. But when I took those "testing" directories away, and wanted to use these others (unversioned), then it failed.

I'm under VS2005 here on XP. Any ideas?

回答1:

Fast answer, for I have no access to a Visual C++ at home.

I believe you are clashing with the "autolinking" of Boost on Visual C++ compilers.

A solution would be to disable "autolink" (see your documentation for that: A quick google search showed the macro "BOOST_ALL_NO_LIB" to disable autolinking for ALL Boost libraries), and then link explicitely your project to the right library.

I'll update this answer as soon as possible.

回答2:

I also ran into this strange (to me) linker error for my build of Boost on Windows Server 2003 using VS2005. I'm using similar bjam command-line options as the OP was, but without the --layout=system option since I don't mind the version info in them (not yet).

The executive summary of the verbiage that follows is: If you see LINK : fatal error LNK1104: cannot open file 'libboost_regex-vc80-mt-gd-1_42.lib', then you need to to specify the same -D compile line options in your downstream application build as Boost's builds do when they build the Boost Regex library. The documentation does not state that AFAICT (as of 2010-03-23).

The details: Things I found quite helpful debugging this problem were:

1. Use the -d+2 option to bjam when building. This dumps out a huge amount of logging about exactly what command-line options are being used. That was how I determined that -DBOOST_ALL_NO_LIB=1 and -DBOOST_REGEX_DYN_LINK=1 were being specified on the cl.exe compile line when building the Boost Regex library.

2. Realize that you have to also supply the same special -D flags (use either -D or /D options which VS2005 accepts as the same thing) when you compile the .cpp files in the app that uses that Boost library (true for Boost Regex, and I am guessing it is true for others, which I have not confirmed). That is why you will see a linker failure of: LINK : fatal error LNK1104: cannot open file 'libboost_regex-vc80-mt-gd-1_42.lib', since without the -DBOOST_ALL_NO_LIB=1 and -DBOOST_REGEX_DYN_LINK=1 options, the auto-linking will kick in when the compiler parses your .cpp file and #include's the Boost header, the latter of which #include's the auto-linking headers, the latter of which by default uses the auto-linking logic which are compiler pragmas that tell the linker which library to use. And guess which ones that auto-linking logic chooses by default? Answer: The static ones that are of the form libblablabla.lib and not blablabla.lib which are the import libraries you expect. This pragma-based linker directive logic is what had me chasing my tail for 3 hours trying to figure out what I did wrong on my linker line, when it is under C-preprocessor control in the auto-linking logic that did it.