Mac上的Qt Creator和Boost库

Question

I am running QtCreator on Mac... I want to start working on boost libraries ... So, I installed boost libraries using

brew install boost

After that I created a small boost hallo world program and made the changes in .pro file as follows

TEMPLATE = app
CONFIG += console
CONFIG -= app_bundle
CONFIG -= qt

unix:INCLUDEPATH += "/usr/local/Cellar/boost/1.55.0_1/include/"
unix:LIBPATH += "-L/usr/local/Cellar/boost/1.55.0_1/lib/"

SOURCES += main.cpp

LIBS += \
-lboost_date_time \
-lboost_filesystem \
-lboost_program_options \
-lboost_regex \
-lboost_signals \
-lboost_system

I am still unable to build... What could be the reason? Please suggest me what could be the possible mistake...

The errors are

library not found for -lboost_data_time
linker command failed with exit code 1 (use -v to see invocation)

Answer 1

This is taking a bit from Uflex's answer, as he missed something. So keep the same code:

//make sure that there is a boost folder in your boost include directory
#include <boost/chrono.hpp>
#include <cmath>

int main()
{
auto start = boost::chrono::system_clock::now();

    for ( long i = 0; i < 10000000; ++i )
        std::sqrt( 123.456L ); // burn some time

    auto sec = boost::chrono::system_clock::now() - start;
    std::cout << "took " << sec.count() << " seconds" << std::endl;

    return 0;
}

But lets change his .pro a bit:

TEMPLATE = app
CONFIG += console
CONFIG -= app_bundle
CONFIG -= qt

SOURCES += main.cpp

macx {
    QMAKE_CXXFLAGS += -std=c++11

    _BOOST_PATH = /usr/local/Cellar/boost/1.55.0_1
    INCLUDEPATH += "$${_BOOST_PATH}/include/"
    LIBS += -L$${_BOOST_PATH}/lib
    ## Use only one of these:
    LIBS += -lboost_chrono-mt -lboost_system # using dynamic lib (not sure if you need that "-mt" at the end or not)
    #LIBS += $${_BOOST_PATH}/lib/libboost_chrono-mt.a # using static lib
}

The only thing I have added to this was the boost system( -lboost_system ) That should solve the issue with his original version causing the undefined symbols, and allow you to add your other libraries.

Such as -lboost_date_time, which for me worked perfectly with the brew install.

Granted, my path is actually: /usr/local/Cellar/boost/1.55.0_2

Answer 2

Boost libraries are modularized, you just need to link against the libraries that you are using. Some libraries are header only , so you don't need to do anything, having boost reachable in your path is enough.

You can try to compile this:

//make sure that there is a boost folder in your boost include directory
#include <boost/chrono.hpp>
#include <cmath>

int main()
{
    auto start = boost::chrono::system_clock::now();

    for ( long i = 0; i < 10000000; ++i )
        std::sqrt( 123.456L ); // burn some time

    auto sec = boost::chrono::system_clock::now() - start;
    std::cout << "took " << sec.count() << " seconds" << std::endl;

    return 0;
}

And in the .pro file:

TEMPLATE = app
CONFIG += console
CONFIG -= app_bundle
CONFIG -= qt

SOURCES += main.cpp

macx {
    QMAKE_CXXFLAGS += -std=c++11

    _BOOST_PATH = /usr/local/Cellar/boost/1.55.0_1
    INCLUDEPATH += "$${_BOOST_PATH}/include/"
    LIBS += -L$${_BOOST_PATH}/lib
    ## Use only one of these:
    LIBS += -lboost_chrono-mt # using dynamic lib (not sure if you need that "-mt" at the end or not)
    #LIBS += $${_BOOST_PATH}/lib/libboost_chrono-mt.a # using static lib
}