I'm trying to compile a C++ file on a Mac that uses opencv2.
I downloaded opencv, found an opencv2 folder in it, and copied it into the folder where main.cpp (the program I'm trying to run is).
The folder structure is:
main.cpp
BRIEF.h
opencv2
core.hpp
core
cvdef.h
My current command (after reading this and this) is g++ -I/opencv2/core.hpp main.cpp, run from within the same folder main.cpp is in.
main.cpp has #include "BRIEF.h" which works fine.
BRIEF.h has #include "opencv2/core.hpp" which works fine.
core.hpp has #include "opencv2/core/cvdef.h" which fails saying the file was not found.
How do I use G++ such that the file can be found?
As you said, you are only including this file/opencv2/core.hpp so it is normal that the compiler fails finding the other files.
In your code you are including your files starting from your project root directory, so you have to include the project root directory for the compiler to find these files:
g++ -I$(PROJECT_DIR) $(PROJECT_DIR)/main.cpp
or if you run g++ from the root directory, you can use ., which will expand into the current path (your project root directory):
g++ -I. main.cpp
Related
I have a simple c++ program. Its not even doing anything, just includes mysql.h.
I compile with this command: g++ -o main main.cpp -I/usr/include/mysql. The include path is correct, thats where mysql.h is. It says no such file or directory and i don't know why.
I am trying to compile a c++ code with a third party library using g++ as a compiler.
My main.cpp needs to include the header file core.hpp while the core.hpp needs to include cvdef.h whereas cvdef.h need to include interface.h.
The paths for these three headers in the include statements are as follows:
#include "opencv2/core.hpp"
#include "opencv2/core/cvdef.h"
#include "opencv2/core/hal/interface.h"
See file structure in image below.
When I compile my main.cpp it finds the core.hpp. The core.hpp, however, cannot seems to find cvdef.h as it is looking within the 'core'-folder for the 'opencv2'-folder (which is a level below).
Without changing the paths in the include statement, how would I go about this?
My current compile statement using g++ under Windows is:
g++ main.cpp -o main
It seems that OpenCV2 wants to look for the header files in standard locations.
You can add to the list of standard locations by using the -I (upper-case i) option, specifying the path to add.
In your case you should be able to do it with
g++ main.cpp -o main -Iopencv2/core
I'm stuck in a very simple problem: I cannot manage to make work my simple code example in C++.
I want to include the "curl" library but when I compile with the command:
g++ -o myprog.out myprog.cpp -L/curl/include/ -lcurl
I get the following error message:
myprog.cpp:3:71: fatal error: /curl/include/curl/curl.h: No such file
or directory
My folder contains:
myprog.cpp (the file I want to compile)
curl -> include -> curl -> curl.h (path in which the curl.h file is located).
My headers file are configured in this way:
include<iostream>
include<string>
include<curl.h>
What I'm doing wrong? It's probably a very simple problem but it's driving me crazy :-/
Change #include <curl.h> to #include <curl/curl.h>.
Change -L/curl/include/ to -I/curl/include.
Add -L/curl/lib -Wl,-rpath=/curl/lib (or whatever the path to curl built libraries).
I am trying to execute a cpp file named "palindrome.cpp" using terminal on my Macbook. This cpp file uses an external library named "libStanfordCPPLib.a" which lies under "DIRECTORY TO CPP FILE/StanfordCPPLib", also the corresponding header files of this library are in this "StanfordCPPLib" folder.
You can see the folder structure by this screenshot:
My code for compiling this source code is :
g++-4.8 -Wall -I/Users/myName/Downloads/CS106B/palindrome/StanfordCPPLib -L/Users/myName/Downloads/CS106B/palindrome/StanfordCPPLib palindrome.cpp libStanfordCPPLib.a
As I understand, -I stands for the directory path where header files exist, and -L stands for the directory path where library (.a file) exists. That's why both -I and -L are the same directory path "/Users/myName/Downloads/CS106B/palindrome/StanfordCPPLib".
However, executing this command returns an error saying :"libStanfordCPPLib.a: No such file or directory". As is shown in the screenshot:
Can anyone see why this happens? Thanks.
Try this, using -lStanfordCPPLib:
g++-4.8 -Wall -I/Users/myName/Downloads/CS106B/palindrome/StanfordCPPLib -L/Users/myName/Downloads/CS106B/palindrome/StanfordCPPLib palindrome.cpp -lStanfordCPPLib
I have a directory maths which is a library that is comprised solely of header files.
I am trying to compile my program by running the following command in my home directory:
g++ -I ../maths prog1.cpp prog2.cpp test.cpp -o et -lboost_date_time -lgsl -lgslcblas
but I get the following compilation error:
prog1.cpp:4:23: fatal error: maths/Dense: No such file or directory
compilation terminated.
prog2.cpp:6:23: fatal error: maths/Dense: No such file or directory
compilation terminated.
maths is located in the same directory(i.e. my home directory) as the .cpp files and I am running the compilation line from my home as well.
prog1.cpp and prog2.cpp have the following headers
#include<maths/Dense> on lines 4 and 6 respectively, hence I am getting the error.
how do I fix it.
You can either change your include path to -I.. or your includes to #include <Dense>
Wait, if maths is in the same directory as your source files and that is your current directory, you can either change your include path to -I. or your includes to #include "Dense"
maths is located in the same directory(i.e. my home directory) as the .cpp files
Your include path is given as -I ../maths. You need -I ./maths – or simpler, -I maths since maths is a subdirectory of the current directory, not of the parent directory. Right?
Then in your C++ file, use #include <Dense>. If you want to use #include <maths/Dense> you need to adapt the include path. However, using -I. may lead to massive problems1, I strongly advise against this.
Instead, it’s common practice to have an include subdirectory that is included. So your folder structure should preferably look as follows:
./
+ include/
| + maths/
| + Dense
|
+ your_file.cpp
Then use -I include, and in your C++ file, #include <maths/Dense>.
1) Consider what happens if you’ve got a file ./map.cpp from which you generate an executable called ./map. As soon as you use #include <map> anywhere in your code, this will try to include ./map instead of the map standard header.