I have 3 files in a folder. one.cpp, one.hpp and main.cpp. one.hpp has a class declaration. one.cpp has definition of functions in the class both under same namespace.Iam calling a function from the class in main and including one.hpp in main. how can compile and run all these files to generate coverage using gcov ?
I tried generating seperate object files and creating an executable .Didn't work
Compiled code using g++ -I. main.cpp one.cpp as John Suggested. To get coverage object after compilation and execution Modified the line as g++ --coverage -I. main.cpp one.cpp.It generated a.out and required .gcna and .gcda files.Generated coverage report as i wanted.Thanks for the help.
Related
Seen this post:
How do you compile a C++ program with multiple class files from OS X Terminal?
I see that to compile with gcc a project with a class (with .h and .cpp) is easy as:
g++ [list of all source files] -o [executableName]
And it actually works for me, but when i try to use Clang:
clang++-11 main.cpp Person.hpp Person.cpp -o main
I get:
clang: error: cannot specify -o when generating multiple output files
NOTE: i know how to use Makefile's, but i would like to have a quick way to compile in Clang like in gcc.
If you run clang++-11 main.cpp Person.hpp Person.cpp -o main with the header file, clang notices this and compiles the pre-compiled header "Person.pch", the default -o Person.pch is implied. Meanwhile you want getting yet another output file "main". Thus, clang complains it can't generate multiple output files, -o Person.pch and -o main.
Pre-compiled headers should be compiled separately.
clang++-11 Person.hpp
clang++-11 main.cpp Person.cpp -o main
The first step is not required, if skipped, no pre-compiled headers are used.
According to How does the compilation/linking process work?
During compilation, the compiler takes the pre-processor's output and
produces an object file from it.
Additionally,
Compilation refers to the processing of source code files (.c, .cc,
or .cpp) and the creation of an 'object' file.
So for example:
If I have 2 files test1.cpp and test2.cpp. I can do modular compilation with g++ -c test1.cpp test2.cpp which generates 2 object files test1.o and test.o.
But what about during single step compilation? Where I have 1 file test1.cpp. With the command g++ test1.cpp, no object file appears to be generated in the directory. So what happens during single step compilation?
This has to do with g++ command line. If you just run it with
g++ file.cpp
It will compile the code to intermediate object file, and than invoke linker and create a.out executable file, removing the intermediate object file after this.
The code::block IDE generates the following files:
./main.cpp
./include/class.h
./src/class.cpp It include class.h with #include "class.h"
How can I run this set of files, with the three files in three different folders?
First, this program can be run by clicking IDE "build and run" button.
This program need to take some arguments, like ./a.out arg[1] arg[2]. So I cannot input arguments by clicking "build and run" button, and thus I have to use g++ to compile an output first.
But g++ is not smart enough as the IDE in finding the three files(I try g++ -I./include main.cpp, it seems that it has no problem with class.h file, but cannot find class.cpp file)
So how can I compile the three files in three different locations?
BTW, how could the class.h file find the class.cpp file in IDE/g++(scan all the files in the directory to see which contains the definition of the class functions?)?
It's a bad idea to #include source files. But this will do it:
g++ -I./include -Isrc main.cpp
Normally one would expect that the IDE has some function to just build the application, especially when there's a function to build-and-run. In addition there are those that have the possibility to supply command line arguments for the program so build-and-run will run with supplied arguments.
You have to supply the source files and the search path for includes, normally one would write:
g++ -o exec-file-name -I./include main.cpp src/class.cpp
but that may depend a bit on how you include the header file. Another note is that you normally don't compile the header file separately - it's included when you compile the .cpp files that includes it.
If on the other hand you actually want to do what you write (compile the .h file that includes the .cpp file - which is higly unorthodox) you would do:
g++ -c -I./src include/class.h
g++ -c main.cpp
g++ -o exec-file-name main.o class.o
where you need to replace the .o extension if your platform uses another extension. Note that in this case you should probably not include class.h from main.cpp since that could lead to duplicate symbols.
I am trying to make my own header file which will contain a class Vector.
To create a header file, as advised by some websites, I have created two different files :-
1) collections.h (contains declarations)
2) collections.cpp (contains definition)
Another file is main.cpp, which contains the main function, and in which I will be using collections.h
All these files are in the same directory
The trouble I am having is that compiler is showing the error
Undefined reference to Vector::Vector(int, int)
and so on for all the functions in my class.
I have made sure that there is a #include "collections.h" line in both collections.cpp as well as main.cpp
How can I solve the above problem?
I am using gcc compiler under ubuntu 12.04
First build the object files:
gcc -c main.cpp -o main.o
gcc -c collections.cpp -o collections.o
then link them together:
gcc collections.o main.o -o main
You need to build both source files and link them together.
On a Linux command line, you can do it simplest by providing both source files to gcc:
$ g++ -Wall main.cpp collections.cpp -o my_program
Note: I added the -Wall option to enable more warnings by default. It's always a very good habit to enable more warnings, as they can often point out logical errors or possible places where you have undefined behavior.
Recently I have tried to compile a program in g++ (on Ubuntu). Usually i use Dev-C++ (on Windows) and it works fine there as long as I make a project and put all the necessary files in there.
The error that occurs when compiling the program is:
$filename.cpp: undefined reference to '[Class]::[Class Member Function]'
The files used are as following:
The source code (.cpp) file with the main function.
The header file with the function prototypes.
The .cpp file with the definitions for each function.
Any help will be appreciated.
You probably tried to either compile and link instead of just compiling source files or somehow forgot something.
Variation one (everything in one line; recompiles everything all the time):
g++ -o myexecutable first.cpp second.cpp third.cpp [other dependencies, e.g. -Lboost, -LGL, -LSDL, etc.]
Variation two (step by step; if no -o is provided, gcc will reuse the input file name and just change the extension when not linking; this variation is best used for makefiles; allows you to skip unchanged parts):
g++ -c first.cpp
g++ -c second.cpp
g++ -c third.cpp
g++ -o myexecutable first.o second.o third.o [other dependencies]
Variation three (some placeholders):
Won't list it but the parameters mentioned above might as well take placeholders, e.g. g++ -c *.cpp will compile all cpp files in current directory to o(bject) files of the same name.
Overall you shouldn't worry too much about it unless you really have to work without any IDE. If you're not that proficient with the command line syntax, stick to IDEs first.
The command line of gcc should look like:
g++ -o myprogram class1.cpp class2.cpp class3.cpp main.cpp
Check in which cpp file the missing class member function is defined. You may have not given it to gcc.
You can also check for correct #include tags within filename.cpp. Assume that filename.cpp uses code contained in myclass.h present in the same directory as filename.cpp. Assume that the class that g++ says is undefined is contained in myclass.h and defined in myclass.cpp. So, to correctly include myclass.h within filename.cpp, do the following:
In filename.cpp:
#include <iostream>
#include <myclass.h>
//..source code.
In the makefile:
filename.o: myclass.C myclass.h filename.cpp
g++ -I./ -c filename.cpp -o filename.o
myclass.o: myclass.C myclass.h
g++ -c myclass.C -o myclass.o
In the above, note the use of -I. option when compiling filename.cpp. The -I<directory> asks g++ to include the path following the -I part into the search path. That way myclass.h is correctly included.
In the absence of more information (the source maybe), it is difficult to say with any accuracy where the problem lies. All attempts will be but stabs in the dark.
I assume that you have declared a member function (usually in a .h or .hpp file) but have ommited the respective definition of the member function (usually in a .cpp file).
In c++, it is possible to declare a class like so:
class foo {
void x();
void y();
}
with a cpp file that goes like so
void foo::x() {
do_something()
}
Note, there is no foo::y().
This poses no problem to the compiling/linking process as long as the member function foo::y() is referenced nowhere throughout the compiled code.