I tried to compile program with https://github.com/yhirose/cpp-httplib "one-header" library. I wrote
#include "httplib.h"
/* example code from main github page */
and when i tried to compile program
g++ -std=c++11 -o test test.cc
i got this error:
/usr/bin/ld: /tmp/ccYMj4l8.o: in function `std::thread::thread<httplib::ThreadPool::worker, , void>(httplib::ThreadPool::worker&&)':
test.cc:(.text._ZNSt6threadC2IN7httplib10ThreadPool6workerEJEvEEOT_DpOT0_[_ZNSt6threadC5IN7httplib10ThreadPool6workerEJEvEEOT_DpOT0_]+0x2f): undefined reference to `pthread_create'
collect2: error: ld returned 1 exit status
What can i do?
And how to link libraries that have include and src directories, e.g. libcurl
It's gcc's known particular feature, its std::thread implementation is built upon pthreads so it requires specifying -pthread to correctly link programs with threads.
Related
I'm a newbie in using MPI, and I want to run my cpp project with mpi. I have a main cpp file which includes the main mpi stuff, and two other cpp files that are needed (and being called) in the main one.
In Ubuntu, I am doing:
mpic++ -o mainFile.cpp otherFile1.cpp otherFile2.cpp
But I am getting this error:
/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-gnu/Scrt1.o: in function `_start': (.text+0x24): undefined reference to `main' collect2: error: ld returned 1 exit status
I have mpic++ installed and I can run some other (one cpp file and very simple) projects, but not this one.
Could you please help?
I'm following this tutorial however it does not state which libaries I need to include in order to get boost to work,current options for links are:
-I/usr/include/opencv2 -I/usr/include/boost_1_55_0 -I/usr/include/boost_1_55_0/boost -O0 -g3 -Wall -c -fmessage-length=0
however this returns the following erro:
which states that it can't find asio, am I doing something wrong or was assio the wrong library to link to? Or is there any other way to find out. Note that this is my 2nd c++ project(through I have a lot of java experience) and first with the heavy use of libraries so details are somewhat required.
Removing boost/asio gave me the following errors:
make all
Building target: DisplayImage
Invoking: GCC C++ Linker
g++ -L/usr/include/opencv2 -L/usr/include/boost_1_55_0/boost -L/usr/include/boost_1_55_0 -L/usr/include/opencv2 -L/usr/lib -o "DisplayImage" ./src/Cap.o ./src/DisplayImage.o ./src/Filters.o ./src/sender.o -lopencv_imgproc -lopencv_highgui -lopencv_core
./src/sender.o: In function `__static_initialization_and_destruction_0':
/usr/include/boost_1_55_0/boost/system/error_code.hpp:222: undefined reference to `boost::system::generic_category()'
/usr/include/boost_1_55_0/boost/system/error_code.hpp:223: undefined reference to `boost::system::generic_category()'
/usr/include/boost_1_55_0/boost/system/error_code.hpp:224: undefined reference to `boost::system::system_category()'
./src/sender.o: In function `error_code':
/usr/include/boost_1_55_0/boost/system/error_code.hpp:323: undefined reference to `boost::system::system_category()'
./src/sender.o: In function `boost::asio::error::get_system_category()':
/usr/include/boost_1_55_0/boost/asio/error.hpp:224: undefined reference to `boost::system::system_category()'
collect2: ld returned 1 exit status
make: *** [DisplayImage] Error 1
Build Finished **
I use an ubuntu (x64) laptop if it matters.
Most of boost is implemented in what's called "header-only" code. Through the generous use of C++ templates, there is no actual library code to which your code needs to link. However, there are, as you've seen some actual libraries as well. Generally, the help you seek is probably here: http://www.boost.org/doc/libs/1_55_0/more/getting_started/unix-variants.html#link-your-program-to-a-boost-library
Your particular program uses the timer and system libraries and so you can probably use this command line to link your program:
g++ timer.cpp -o timer -lboost_timer -lboost_system
You can look at the bjam in boost/libs/asio/example/cpp03/tutorial/Jamfile.v2:
project
: requirements
<library>/boost/system//boost_system
<library>/boost/thread//boost_thread
<define>BOOST_ALL_NO_LIB=1
<threading>multi
<os>SOLARIS:<library>socket
<os>SOLARIS:<library>nsl
<os>NT:<define>_WIN32_WINNT=0x0501
<os>NT,<toolset>gcc:<library>ws2_32
<os>NT,<toolset>gcc:<library>mswsock
<os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
<os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
<os>HPUX:<library>ipv6
;
You can see that they build all the tutorial steps with
-lboost_system -lboost_thread -DBOOST_ALL_NO_LIB=1
on linux
I am new to posix thread library, and I tried to compile a sample code from a tutorial with:
g++ -lpthread agreement.cpp -o agreement
however I was not able to compile the code and got the following error message:
a3q2.cpp:(.text+0x7e): undefined reference to `sem_open'
a3q2.cpp:(.text+0xab): undefined reference to `sem_wait'
a3q2.cpp:(.text+0x290): undefined reference to `sem_post'
a3q2.cpp:(.text+0x2af): undefined reference to `sem_close'
a3q2.cpp:(.text+0x2bb): undefined reference to `sem_unlink'
collect2: ld returned 1 exit status
make: *** [a3q2_exe] Error 1
I am aware that -lpthread is needed for compilation to work, but is there any other options i might need to solve the problem? if not how do I have to install the "proper" pthread library?
Thanks for your help!
You want the compile option -pthread (if you are really using pthreads). If you just need those functions they are in librt so use -lrt
I'm trying access an extern device via a serial port and want to use Boost.Asio for this propose.
I have build the boost libraries for MinGw and compiled the regex example successful.
But I have problems to compile my code if I include something from Boost.Asio:
#include <boost/asio/serial_port.hpp>
int main() {
return 0;
}
g++ -D _WIN32_WINNT=0x0501 -O0 -g3 -Wall -c -fmessage-length=0 -osrc\SerialPortTest.o ..\src\SerialPortTest.cpp
g++ -LC:\boost-libs\boost\bin.v2\libs\thread\build\gcc-mingw-4.5.2\release\link-static\threading-multi -LC:\boost-libs\boost\bin.v2\libs\system\build\gcc-mingw-4.5.2\release\link-static\threading-multi -oSerialPortTest.exe src\SerialPortTest.o -lboost_thread-mgw45-mt-1_48 -lboost_system-mgw45-mt-1_48
src\SerialPortTest.o: In function `ZN5boost4asio6detail17winsock_init_base7startupERNS2_4dataEhh':
c:/mingw/bin/../lib/gcc/mingw32/4.5.2/../../../../include/boost/asio/detail/impl/winsock_init.ipp:39: undefined reference to `WSAStartup#8'
src\SerialPortTest.o: In function `ZN5boost4asio6detail17winsock_init_base7cleanupERNS2_4dataE':
c:/mingw/bin/../lib/gcc/mingw32/4.5.2/../../../../include/boost/asio/detail/impl/winsock_init.ipp:48: undefined reference to `WSACleanup#0'
collect2: ld returned 1 exit status
For me it seems to be a linking problem, but I don't get it.
Add -lws2_32 flag to link against WinSockets library.
Also, this might be useful: MinGW linker error: winsock
You miss wsock32 library. Add this to your dependencies and it should work.
I am trying to compile a simple ssl program (it was taken from the openssl book source code).
The program has the following files: common.h common.c client.c server.c
I have installed openssl 0.9.7 so I have the same version with the book.
I have downloaded the source and ./Configure, make, make test, make install in the home directory.
In the common.h there are the following includes:
#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/rand.h>
#include <openssl/ssl.h>
#include <openssl/x509v3.h>
I run gcc -Wall common.c client.c -o client but I get the following errors:
common.c: In function ‘init_OpenSSL’:
common.c:12:5: warning: implicit declaration of function ‘THREAD_setup’
/tmp/ccvI3HX4.o: In function `handle_error':
common.c:(.text+0x3a): undefined reference to `ERR_print_errors_fp'
/tmp/ccvI3HX4.o: In function `init_OpenSSL':
common.c:(.text+0x51): undefined reference to `THREAD_setup'
common.c:(.text+0x5a): undefined reference to `SSL_library_init'
common.c:(.text+0x97): undefined reference to `SSL_load_error_strings'
/tmp/ccRA0Co9.o: In function `do_client_loop':
client.c:(.text+0x71): undefined reference to `BIO_write'
/tmp/ccRA0Co9.o: In function `main':
client.c:(.text+0xbb): undefined reference to `BIO_new_connect'
client.c:(.text+0x106): undefined reference to `BIO_ctrl'
client.c:(.text+0x18e): undefined reference to `BIO_free'
collect2: ld returned 1 exit status
Obviously it cannot link to the header files...
When I run as suggested in one forum gcc -Wall common.c client.c -o client -lcrypto -lssl I get
common.c: In function ‘init_OpenSSL’:
common.c:12:5: warning: implicit declaration of function ‘THREAD_setup’
/tmp/cc2gjx8W.o: In function `init_OpenSSL':
common.c:(.text+0x51): undefined reference to `THREAD_setup'
collect2: ld returned 1 exit status
But adding -lpthread won't help resolve the problem...
Any idea why this happens and how to solve it?
My guess is that lcrypto and lssl are installed by default in ubuntu and by doing -lcypto is telling the linker to look at the systems headers and not the openssl installation ones...
Any help or pointers is appreciated!
Thank you!
In some code versions of openssl book, the thread related functions are stored in reentrant.c, (in fact the declaration of TRHEAD_setup, in the version i've seen is there), so try with:
gcc -Wall common.c client.c reentrant.c -o client -lcrypto -lssl