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?
Related
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.
I get following error, when i tried to compile my test program
g++ main.cpp -o main
/tmp/ccICBwKO.o: In function `main':
main.cpp:(.text+0xa): undefined reference to `ssh_new'
main.cpp:(.text+0x2d): undefined reference to `ssh_free'
collect2: error: ld returned 1 exit status
make: *** [main] Error 1
In my make file i have:
all: main
$main: main.cpp
g++ main.cpp -o main -lssh
Thanks for help. (I really hate C/C++...)
As you can see from the log, make is not using the rule you have given for $main. I suspect that you want to name it either main or $(main).
$main concatenates the value of variable $m (defaults to nothing as m is not defined) with ain, so that you've created a rule for ain instead of main. make thus rely on its default rules for creating an executable from a .cpp file, which does not include linking with libssh.
I am trying to use the SDL_ttf development library in an Ubuntu environment. I started by downloading the dev libraries via: sudo apt-get install libsdl-ttf2.0-dev.
Next, I imported the header file in my code as so:
#include <SDL_ttf.h>
When I compile with the command:
g++ -g -I /usr/include/SDL Main.cpp -lSDL -lSDL_image -lSDL_ttf land.cpp PerlinNoise.cpp Util.cpp org.cpp Init.cpp `sdl-config --libs
I get the following output:
/tmp/ccpLKljA.o: In function `init()':
/home/zoo/Desktop/World-A/Util.cpp:39: undefined reference to `TTF_Init'
/home/zoo/Desktop/World-A/Util.cpp:42: undefined reference to `TTF_Quit'
/home/zoo/Desktop/World-A/Util.cpp:48: undefined reference to `TTF_OpenFont'
/home/zoo/Desktop/World-A/Util.cpp:52: undefined reference to `TTF_Quit'
collect2: ld returned 1 exit status
I understand this is a linker error however I do not know what to do to fix it. I know that the -lSDL_ttf command is not doing anything because removing it does not change anything. I tried to reference the .so file however that didn't change the results. I did this reference via the command: -LlibSDL_ttf-2.0.so.0.6.3. I am able to view the .so file and it does contain the commands listed above.
You have to put land.cpp, and the rest of the CPP files, before the libraries on the command line.
I have the problem that as the g++ tries to link the object files I receive the following error:
11:29:13 **** Build of configuration Debug for project daytime ****
make all
'Building target: daytime'
'Invoking: Cross G++ Linker'
g++ -o "daytime" ./tcf/services/daytime.o ./tcf/main/main.o
./tcf/services/daytime.o: In function `command_get_time_of_day':
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:38: undefined reference to `json_read_string'
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:40: undefined reference to `exception'
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:43: undefined reference to `exception'
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:52: undefined reference to `write_stringz'
makefile:46: recipe for target 'daytime' failed
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:54: undefined reference to `write_stringz'
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:56: undefined reference to `write_errno'
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:58: undefined reference to `json_write_string'
./tcf/services/daytime.o: In function `ini_daytime_service':
C:\Users\falkstef\runtime-EclipseApplication\daytime\Debug/../tcf/services/daytime.c:70: undefined reference to `add_command_handler'
collect2.exe: error: ld returned 1 exit status
make: *** [daytime] Error 1
I have no idea why this is the case since e.g. #include <tcf/framework/json.h>is included and found.
Didn't gcc compile the corresponding *.c files such that this linker error occurs?
What is the problem here?
Thank you.
It is not enough to include the header files; you also have to specify the libraries where those functions are defined.
To make the linker find all those methods/classes (json_read_string, write_stringz, exception) you need to reference the library. If e.g. they are contained in a library called libjson.so, you should do:
g++ -ljson -o "daytime" ./tcf/services/daytime.o ./tcf/main/main.o
(or add the library to the project options, if eclipse is managing your make files).
Or if it's another .o file, include that in the compilation (-> or in the project, if eclipse is creating the make file).
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