g++ cannot find header file

Question

I am migrating from Java to C++. It seems that C++ makes classes declaration in separate files, difficult. So I need your help,

in my main.cpp:

#include "Sphere.h"

using namespace std;
.....
...
..

int main( void ) {
   Sphere *earth = new Sphere(sphere_start ,sphere_end);
...
..
.

in my Sphere.h

class Sphere
{

    public:
        Sphere(int,int);

}

and in my Sphere.cpp

#include "Sphere.h"

using namespace std;

int sphere_start, sphere_end;   

Sphere::Sphere (int a, int b)
{
    sphere_start = a;
    sphere_end = b;
}

void Sphere::render(int i) 
{
   ....
   ..
   .

}

This is the very basic code that I think causes the following error:

main.cpp:14:20: fatal error: Sphere.h: No such file or directory
compilation terminated.

why?

stefanB · Answer 1 · 2012-01-05T05:15:58.403

6

You need to add to your compile command a path to where the header files can be found.

If your header is in the headers directory add -Iheaders:

g++ -o main.o -c -Iheaders main.cpp
g++ -o sphere.o -c -Iheaders sphere.cpp
g++ -o app main.o sphere.o -L.

Or whatever your files are ...

edited Jan 05 '12 at 05:15

answered Jan 05 '12 at 00:37

stefanB

77,323
27
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score 4 · Accepted Answer · answered Jan 05 '12 at 00:35

4

Sphere.h must either be in the same directory as each file that includes it, or the compiler must be directed to search the directory in which Sphere.h is located.

answered Jan 05 '12 at 00:35

01d55

1,872
13
22

3

all the file are in the same directory – Test Test Jan 05 '12 at 00:38
How one could "debug" this problem, when it is clear that all header files are in place, all necessary dev-packages installed and the source file refer to the correct header path, but the compiler still fails to find the header file. – Adam L. S. Jan 10 '14 at 20:28
@AdamL.S. If a compiler fails to find a header file that exists in a known path, the probable cause is failure to specify the root of the path in the compiler invocation. Conventionally, the option is -I. e.g. if header foo.h exists in /usr/include, #include will fail unless either the option -I/usr/ is used, or the compiler is invoked in /usr/. – 01d55 Feb 20 '14 at 20:10

score 2 · Answer 3 · answered Jan 05 '12 at 00:36

2

You should post your command line, but my guess is that you should tell the path to the header files to the compiler. If you're using linux try this:

g++ main.cpp shpere.cpp -I<path_to_Sphere.h> -o main

answered Jan 05 '12 at 00:36

Flamínio Maranhão

337
4
11

score 1 · Answer 4 · answered Jan 05 '12 at 00:35

1

Two potential errors:

Is Sphere.h in the same directory as main.cpp?
Is Sphere.h named Sphere.h and not sphere.h?

answered Jan 05 '12 at 00:35

Laserallan

11,072
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g++ cannot find header file

4 Answers4

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