#include with <> or "" ?

**Jerry Coffin** · Aug 1 '08, 02:45 PM

Re: #include with <> or "" ?

In article <48931c71$0$902 71$14726298@new s.sunsite.dk>, asdff@asd.com
says...

I have a folder 'app' containing a file 'main.cpp' and a subfolder 'types'
(containing various header files). In main.cpp some header files from the
subdir 'types' are included like:
>
1)
#include<types/vector.h>
#include<types/matrix.h>
>
But I have to change them to
>
2)
#include "types/vector.h"
#include "types/matrix.h"
>
to make compilation work.

This is what you almost certainly _should_ do. To make it work with the
angle brackets, you have to lie to the compiler and tell it that the
current diretory (i.e. the parent of your 'types' directory) contains
"system" headers. That's typically done with the the '-I' compiler flag,
though that varies and isn't really topical here anyway.

--
Later,
Jerry.

The universe is a figment of its own imagination.

**Victor Bazarov** · Aug 1 '08, 02:45 PM

Re: #include with <> or "" ?

saneman wrote:

I have a folder 'app' containing a file 'main.cpp' and a subfolder 'types'
(containing various header files). In main.cpp some header files from the
subdir 'types' are included like:
>
1)
#include<types/vector.h>
#include<types/matrix.h>
>
But I have to change them to
>
2)
#include "types/vector.h"
#include "types/matrix.h"
>
to make compilation work. I know that 1) worked earlier with the original
makefile but I don't have that anymore. How is it possible to make the code
compile with the version used in 1) again?
>
I am currently working in MS Visual Studio 2008 and it seems that makefiles
are generated automatically.

The difference in processing of the angle-bracket type inclusion
directives and the double-quote type is *implementation-defined*. It is
not specified in the language Standard how those are different and what
to do in the case like yours. Please post to the newsgroup that deals
with your compiler. IIRC, VC++ looks in the project directory for the
quoted type and in the "include" directories for the bracketed type, so
you might need to add your current directory to the "list of include
directories" (see /I compiler option).

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

**Greg Comeau** · Aug 1 '08, 03:15 PM

Re: #include with <> or "" ?

In article <48931c71$0$902 71$14726298@new s.sunsite.dk>,
saneman <asdff@asd.comw rote:

>I have a folder 'app' containing a file 'main.cpp' and a subfolder 'types'
>(containing various header files). In main.cpp some header files from the
>subdir 'types' are included like:
>
>1)
>#include<typ es/vector.h>
>#include<typ es/matrix.h>
>
>But I have to change them to
>
>2)
>#include "types/vector.h"
>#include "types/matrix.h"
>
>to make compilation work. I know that 1) worked earlier with the original
>makefile but I don't have that anymore. How is it possible to make the code
>compile with the version used in 1) again?
>
>I am currently working in MS Visual Studio 2008 and it seems that makefiles
>are generated automatically.

The intention of <is to search for "system header files"
whereas the intention of "" is to search for "other headers".
The problem is that a lot of this is left to the implementation
and not dictated by the standard, and as such, it is not completely
specified and the can even cross over to the other form
(IOWs, putting a system header files within "" and as on).
In short, it's left up to the implementation to document.
So the answer to your question is compiler specific, however,
that said, chances are good that you can getting it working with
a -I option, though the argument is that you probably should
prefer form (2).
--
Greg Comeau / 4.3.10.1 with C++0xisms now in beta!
Comeau C/C++ ONLINE == http://www.comeaucomputing.com/tryitout
World Class Compilers: Breathtaking C++, Amazing C99, Fabulous C90.
Comeau C/C++ with Dinkumware's Libraries... Have you tried it?

**James Kanze** · Aug 1 '08, 04:45 PM

Re: #include with <> or "" ?

On Aug 1, 4:44 pm, Victor Bazarov <v.Abaza...@com Acast.netwrote:

saneman wrote:

I have a folder 'app' containing a file 'main.cpp' and a
subfolder 'types' (containing various header files). In
main.cpp some header files from the subdir 'types' are
included like:

1)
#include<types/vector.h>
#include<types/matrix.h>

But I have to change them to

2)
#include "types/vector.h"
#include "types/matrix.h"

to make compilation work. I know that 1) worked earlier with
the original makefile but I don't have that anymore. How is
it possible to make the code compile with the version used
in 1) again?

I am currently working in MS Visual Studio 2008 and it seems
that makefiles are generated automatically.

The difference in processing of the angle-bracket type
inclusion directives and the double-quote type is
*implementation-defined*.

In theory. In practice: includes in a <are searched first in
a list of directories that you provide (via -I or /I options,
depending on the compiler), then in some standard system places
(where the compiler is installed, then /usr/include under most
Unix; under Windows, at least with VC++, I think the contents of
the environement variable INCLUDE). An include "" first
searches in the directory where the file containing the include
was situated, and then acts exactly like an include <>.

Some compilers have additional options to modify this somewhat
(e.g. adding a directory which is only used by include ""), but
I've yet to find a compiler which didn't support the above.

--
James Kanze (GABI Software) email:james.kan ze@gmail.com
Conseils en informatique orientée objet/
Beratung in objektorientier ter Datenverarbeitu ng
9 place Sémard, 78210 St.-Cyr-l'École, France, +33 (0)1 30 23 00 34

#include with <> or "" ?

#include with <> or "" ?

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