I’ve already downloaded Bonmin-1.8.8 and compiled it. The usersmanual said that there is a cpp example in the /bonmin/examples/cppexample.I added the bin and lib to my Path but when I coded
g++ mybonmin.cpp -o mybonmin
It shows that cannot find the headfile. I want to know how can I run Bonmin with the cpp program.
Try passing the flag to the headers:
g++ mybonmin.cpp -I/home/mybonmin -o mybonmin
here more info about it:
-I [/path/to/header-files]
Related
I'm trying to generate a mex function usigin external libraries. I'm using Ubuntu 18 and Matlab R2021a.
In particular I want to compile my file.cpp that uses my cpp library called model.
What I did is
mex -I<path_library_include> -L<path_library_so_file> -lmodel.so -lboost_system -lstdc++ file.cpp -v
where in -I i put the path where is the include of the library in -L the path in which the libmodel.so is located, then I added 2 more libraries and at the end the source file that I want to compile.
In this way I can compile my source but when I try to execute the mex function I get:
libmodel.so: cannot open shared object file: No such file or directory
I also tested the library outside matlab and works fine, this is the command that I use to compile the library outside Matlab
gcc -Wall -I<path_library_include> -L<path_library_so_file> main.cpp -lmodel -lboost_system -lstdc++ -o main
What could be the problem with Matlab?
Thanks to 273K that gave me the right direction.
The problem was that the LD_LIBRARY_PATH was not configured well in fact running /sbin/ldconfig -v my library was not present. So to add the shared library i created a new file as root in /etc/ld.so.conf.d/ called mylib.conf it is not important the name just the extension. Then I run
sudo ldconfig
after that the library was present in fact running
/sbin/ldconfig -v | grep model
where model is the name of my library. it is possible to see the output.
I've just inherited some C++ code that was written poorly with one cpp file which contained the main and a bunch of other functions. There are also .h files that contain classes and their function definitions.
Until now the program was compiled using the command g++ main.cpp. Now that I've separated the classes to .h and .cpp files do I need to use a makefile or can I still use the g++ main.cpp command?
list all the other cpp files after main.cpp.
ie
g++ main.cpp other.cpp etc.cpp
and so on.
Or you can compile them all individually. You then link all the resulting ".o" files together.
To compile separately without linking you need to add -c option:
g++ -c myclass.cpp
g++ -c main.cpp
g++ myclass.o main.o
./a.out
Now that I've separated the classes to .h and .cpp files do I need to use a makefile or can I still use the "g++ main.cpp" command?
Compiling several files at once is a poor choice if you are going to put that into the Makefile.
Normally in a Makefile (for GNU/Make), it should suffice to write that:
# "all" is the name of the default target, running "make" without params would use it
all: executable1
# for C++, replace CC (c compiler) with CXX (c++ compiler) which is used as default linker
CC=$(CXX)
# tell which files should be used, .cpp -> .o make would do automatically
executable1: file1.o file2.o
That way make would be properly recompiling only what needs to be recompiled. One can also add few tweaks to generate the header file dependencies - so that make would also properly rebuild what's need to be rebuilt due to the header file changes.
.h files will nothing to do with compiling ... you only care about cpp files... so type g++ filename1.cpp filename2.cpp main.cpp -o myprogram
means you are compiling each cpp files and then linked them together into myprgram.
then run your program ./myprogram
I know this question has been asked years ago but still wanted to share how I usually compile multiple c++ files.
Let's say you have 5 cpp files, all you have to do is use the * instead of typing each cpp files name E.g g++ -c *.cpp -o myprogram.
This will generate "myprogram"
run the program ./myprogram
that's all!!
The reason I'm using * is that what if you have 30 cpp files would you type all of them? or just use the * sign and save time :)
p.s Use this method only if you don't care about makefile.
You can still use g++ directly if you want:
g++ f1.cpp f2.cpp main.cpp
where f1.cpp and f2.cpp are the files with the functions in them. For details of how to use make to do the build, see the excellent GNU make documentation.
As rebenvp said I used:
g++ *.cpp -o output
And then do this for output:
./output
But a better solution is to use make file. Read here to know more about make files.
Also make sure that you have added the required .h files in the .cpp files.
You can use several g++ commands and then link, but the easiest is to use a traditional Makefile or some other build system: like Scons (which are often easier to set up than Makefiles).
If you want to use #include <myheader.hpp> inside your cpp files you can use:
g++ *.cpp -I. -o out
I used to use a custom Makefile that compiled all the files in current directory, but I had to copy it in every directory I needed it, everytime.
So I created my own tool - Universal Compiler which made the process much easier when compile many files.
You can do that using a single command assuming all the needed .cpp and .h files are in the same folder.
g++ *.cpp *.h -Wall && ./a.out
It will compile and execute at the same time.
when using compiler in the command line, you should take of the following:
you need not compile a header file, since header file gets substituted in the script where include directive is used.
you will require to compile and link the implementation and the script file.
for example let cow.h be header file and cow.cpp be implementation file and cow.cc(c++ files can have extension .cpp, .cc, .cxx, .C, .CPP, .cp) be script file.
Since gcc compiler notation for c++ file is g++, we can compile and link the files using
$g++ -g -Wall cow.cpp cow.cc -o cow.out
options '-g' and '-Wall' are for debugging info and getting warning for errors. Here cow.out is the name of the executable binary file that we can execute to run the program. it is always good to name your executable file otherwise name will be automatically given which might be confusing at times.
you can also do the same by using makefiles, makefiles will detect, compile and link automatically the specified files.
There are great resources for compilation using command line
enter link description here
~/In_ProjectDirectory $ g++ coordin_main.cpp coordin_func.cpp coordin.h
~/In_ProjectDirectory $ ./a.out
... Worked!!
Using Linux Mint with Geany IDE
When I saved each file to the same directory, one file was not saved correctly within the directory; the coordin.h file. So, rechecked and it was saved there as coordin.h, and not incorrectly as -> coordin.h.gch. The little stuff.
Arg!!
I have 2 cpp files(with one main function) in /home/misha/proga/c++again folder. I built C/C++: g++ build active task and modified it to compile all files in the folder above. Now, I need to add one more task to call a binary. I think I should add one more entry in "tasks" to finally be able to run a code. Where can I read about how to write this second task? I am new to programming. Is my approach correct to run this code contained in two files? I also do not know where this binary lies. Is it tasks file in .vscode folder ?
I use Ubuntu 19.10 and VSC 1.46.1
In Terminal,
cd /home/misha/proga/c++again
Let's suppose your two cpp files are mainFile.cpp and file2.cpp
If g++ (so GCC) was not installed in your system, you can install it by running this command on the Terminal:
sudo apt-get install gcc g++
and, to compile the program (read about invoking GCC, you want warnings and debug information), write this command into the Terminal:
g++ -Wall -g mainFile.cpp file2.cpp -o yourprog
Then, you can run the program by typing:
./yourprog
It should work now. You could need to use the GDB debugger and GNU make (to be installed with sudo apt-get install gdb make)
Read also some C++ programming book and this C++ reference.
I do not understand your approach usualy your create a makefile and compile your cpp files
g++ -g -c -fpic -o name.o
at the end you link them
g++ name.o 2name.o and so on
If you create binarys you should store them in /usr/lib
and the name should libname.so you can acces them by using the -l argument
Good Day Everyone,
N.B - This problem has been solved - I have provided my own solution in the answer section however the solution provided by Jonathan is much shorter. Nevertheless, this was the following question I originally posted:
I am basically trying to compile a serial library (for UART communication) on Linux however I am not really sure how to correctly compile (I have mentioned what I have done so far below), any suggestions would be highly valuable. I am using the serialib library - which is composed of 2 main files (serialib.h and serialib.cpp) , you may directly view the source code of these files here (scroll all the way to the bottom and view the files in new tabs): http://serialib.free.fr/html/classserialib.html
I transferred these files (serialib.h and serialib.cpp) to my BeagleBone Black micro-controller which is running Debian (Wheezy) , g++/gcc (Debian 4.6.3-14) 4.6.3. I wrote my own program (uart.cpp is my file name) to access the functions provided by this library, this is what I wrote:
#include <iostream>
#include "serialib.h"
#ifdef __linux__
#define DEVICE_PORT "/dev/ttyO1"
#endif
int main()
{
serialib LS;
return 0;
}
So as you can see I am trying to access the 'seriallib' class. serialib.h, serialib.cpp and uart.cpp are all in the home directory. I also manually added the iostream library in serialib.cpp as I did not see it being declared in the original source code.
Now I am really unsure of how to compile such external libraries but so far I tried the following steps:
g++ -c -Wall -Werror -fPIC serialib.c to convert to PIC which gives the following error:
distcc[3142] (dcc_parse_hosts) Warning: /home/debian/.distcc/zeroconf/hosts contained no hosts; can't distribute work
distcc[3142] (dcc_zeroconf_add_hosts) CRITICAL! failed to parse host file.
distcc[3142] (dcc_build_somewhere) Warning: failed to distribute, running locally instead
g++ serialib.cpp -L /home/debian/serialib.h which gives the following error:
/usr/lib/gcc/arm-linux-gnueabihf/4.6/../../../arm-linux-gnueabihf/crt1.o: In function _start':
(.text+0x30): undefined reference tomain'
collect2: ld returned 1 exit status
distcc[3210] ERROR: compile serialib.cpp on localhost failed
As of now I am still finding out how to compile this and if I manage to work this out then I'll post my solution here too. Once again any suggestion will be highly valuable. Thank you all :) .
g++ -c -Wall -Werror -fPIC serialib.c to convert to PIC which gives the following error:
The "error" is not an error, it's a warning, telling you that your distcc setup is broken, but that it compiled locally.
That command doesn't "convert to PIC", it compiles the file serialib.c and produces a compiled object file, serialib.o
g++ serialib.cpp -L /home/debian/serialib.h
This is just nonsense. It tries to build a program from serialib.cpp and use the directory /home/debian/serialib.h (which isn't a directory!) to find libraries.
You don't need to "compile a library" you can just compile both the source files and link them together into a program. Either:
g++ -c serialib.cpp
g++ -c uart.cpp
g++ serialib.o uart.o -o uart
Or all in one command:
g++ serialib.cpp uart.cpp -o uart
You should read An Introduction to GCC to understand the commands, not just enter bogus commands without understanding them.
I have found a solution to this problem, hope this helps for all the future readers with similar problems. I have my own source code uart.cpp (Given in the question) which I want to compile, the external library is serialib that contains two main files (serialib.h and serialib.cpp), you will want to replace the following commands with respect to the files you have
Step 1: Compiling with position independent code
g++ -c -Wall -Werror -fpic serialib.cpp
Step 2: Creating a shared library
g++ -shared -o libserialib.so serialib.o , here the library is libserialib.so.
Step 3: Linking your source code with library
g++ -L /home/debian -lserialib uart.cpp -o uart
g++ -L /home/debian -Wall -o test uart.cpp -lserialib
You may save the library at a different path and you may have a different name of course. Suppose you have a library called libabc.so at the directory /home/user/myDir then the commands will be like:
g++ -L /home/user/myDir -labc your_code.cpp -o your_code
g++ -L /home/user/myDir -Wall -o test your_code.cpp -labc
test is out own program, lserialib is actually looking for libserialib.so and not serialib.o as gcc/g++ assumes all libraries start with lib and end with .so or .a and you can see the same goes for labc as it will look for libabc.so thus it is important to make sure your library name begins with lib and ends with .so or .a
Step 4: Making library available at run time
Here we provide the path where the library is actually stored, I saved it in the directory /home/debian which is why my command looks like:
export LD_LIBRARY_PATH=/home/debian:$LD_LIBRARY_PATH
if your library is saved at /path/to/file then the command will look like:
export LD_LIBRARY_PATH=/path/to/file:$LD_LIBRARY_PATH
This is to help the loader find the shared library and to view this path: echo $LD_LIBRARY_PATH and to unset this: unset LD_LIBRARY_PATH
To execute the program type either ./test or ./uart and in case of any modification to the main source code (uart.cpp in this case) , simply repeat step 3. I found the following link very useful: http://www.cprogramming.com/tutorial/shared-libraries-linux-gcc.html . Thank you to all of you who took time to read this question and especially those who gave me suggestions. If anyone has more or better solutions, feel free to post them here to assist future readers :).
My Problem
I read somewhere that to add include paths to g++ you need to use the -I option:
g++ -I /some/directory and_then_my_files.cpp
However, I'm not sure if this is actually what I need. It's currently not working for me, and I couldn't find anything else close to what I have.
My Setup
I've got a directory with all my current project code, and in it a subdirectory classes, that contains various .h and .cpp files containing classes that may or may not be used when compiling my main files.
Since g++ ./classes/*.cpp main.cpp takes a long time (large number of files in classes directory), I'm looking for an alternative that only compiles and links the files that are included in the main file.
Main file:
#include "classes/a.h"
#include "classes/b.h"
// ... my code
And as you can imagine, g++ complains about undefined references to classes A and B, unless I add ./classes/*.cpp to the build command.
What I want to achieve
So -I and -L did not work, and adding the whole directory to the build command results in a ridiculously long build time - I'm talking 3-5 minutes, which really slows down my development speed.
Is there any way to only build/link the included classes from my classes directory, such as only classes A and B from the example I gave above?
Small Recap of what I've already tried
g++ -I ./classes main.cpp -o main
g++ -L ./classes main.cpp -o main (probably stupid but I tried it anyway)
g++ ./classes/*.cpp main.cpp -o main (what I currently have to resort to)
Thanks in advance :)
A temporary workaround
export CPLUS_INCLUDE_PATH=/usr/local/include