Include Question

[aggarwv]

I am trying to compile someone else's code and compiler is giving an error on a statement

#include "$INCLUDE"

Can someone please tell me what this statement does? Does it mean that INCLUDE is defined in some other file as a file name? But then one could just do #include INCLUDE I suppose. I have tried searching all files for where INCLUDE may have been defined (using GREP), however I haven't found this which leads me to believe this is doing something else.

Thanks
Vipin

[sicarie]

I'm not sure I understand you. Are you looking for your header files, or are you trying to include a specific library?

#include is a compiler directive - it tells (I'm guessing that using grep, you're using Linux and GCC/G++) GCC/G++ to look in it's library files for the name specified (where your '$INCLUDE' is located - GCC would look for a library named $INCLUDE, which I'm pretty sure doesn't exist). The most common is dependent on your language (GCC or G++). If you are using C, it's #include <stdio.h>, and C++ is #include <iostream>.

Does that help? What are you trying to do?

[weaknessforcats]

This doesn't look like standard C or C++.

Normally, you just include the file name. The file is searched for along a pre-defined path if you use < > in the include. The file is searched for in the present working directory (PWD) if you use " " in the include. In this second case, if the file is not in the PWD, the search continues as though you had used < >.

You are allowed to use a token sequence. Here you include the token leaving you free to redefine the token without having to alter the source file:

#include MYFILE

Somehwhere earlier you have:

#define MYFILE "C:/DooDah/MyStuff/hotwater.h"

And presto, hotwater.h is included.

But the token is not inside double quotes as your example shows. A token inside quote is invalid preprocessor syntax. That is, the token name must resolve to a name between " " or < >.

[oler1s]

You know what I thought when I saw that include line? PHP. Because "$something" is basically a form of string substitution in PHP.

There's three forms of comments in PHP. Yes, # is a single line comment.
PHP has includes. It's just include "something". Include is a function, so you can apply string substitution to the argument.
PHP can do string substitution if double quoted strings are used. And $something gets replaced by whatever the variable $something is for.

I'm not saying that's a PHP line of code. I'm saying, I get the feeling the OP is not a programmer, and doesn't know what he's dealing with.