#define a macro that #includes

[.rhavin grobert]

first of all: sorry for perhaps posting something already answered
anywhere, i couldnt find any useful info - define, macro, include and
so on are very poor keywords;-)

my problem:

i want to do something like...

INCLUDE_TYPES(#include);

....that resolves to ...

#include "file1.h"
#include "file2.h"
#include "file3.h"
.... and my try was a...

#define INCLUDE_TYPES(Q_L) \
Q_L "file1.h" \
Q_L "file2.h" \
Q_L "file3.h" \

....but my compiler complains about...

'#' : invalid character : possibly the result of a macro expansion

....so that way dont work. i cant do a simple...

#include "files.h"

....with all other includes in that file so im looking for some
different idea and would appreciate any useful help.

TIA, -.rhavin;-)

[jxh]

On Apr 10, 10:41*am, ".rhavin grobert" <[e-mail]:

>
my problem:

i want to do something like...

INCLUDE_TYPES(#include);

...that resolves to ...

#include "file1.h"
#include "file2.h"
#include "file3.h"

... and my try was a...

#define INCLUDE_TYPES(Q_L) \
Q_L "file1.h" \
Q_L "file2.h" \
Q_L "file3.h" \

...but my compiler complains about...

*'#' : invalid character : possibly the result of a macro
expansion

...so that way dont work.

Right. You can't expand a preprocessor macro into a
preprocessor directive. You can use the presence of
a macro to determine whether or not to include your
header files by:

#ifdef INCLUDE_TYPES
# include "file1.h"
# include "file2.h"
# include "file3.h"
#endif

i cant do a simple...

#include "files.h"

...with all other includes in that file so im looking for some
different idea and would appreciate any useful help.

You need to explain why you can't do that.

-- James

[Walter Roberson]

In article <5d**********************************@1g2000prg.go oglegroups.com>,
..rhavin grobert <cl***@yahoo.dewrote:

>my problem:

>i want to do something like...

>INCLUDE_TYPES(#include);

>...that resolves to ...

>#include "file1.h"
#include "file2.h"
#include "file3.h"

You cannot do that. No macro can expand to a preprocessor directive.
--
"Walter is a great man." -- Dennis Green

[Harald van =?UTF-8?b?RMSzaw==?=]

On Thu, 10 Apr 2008 10:41:30 -0700, .rhavin grobert wrote:

first of all: sorry for perhaps posting something already answered
anywhere, i couldnt find any useful info - define, macro, include and so
on are very poor keywords;-)

my problem:

i want to do something like...

INCLUDE_TYPES(#include);

...that resolves to ...

#include "file1.h"
#include "file2.h"
#include "file3.h"

That's not possible in C. Macro expansions cannot ever generate
preprocessing directives.

... and my try was a...

#define INCLUDE_TYPES(Q_L) \
Q_L "file1.h" \
Q_L "file2.h" \
Q_L "file3.h" \

...but my compiler complains about...

'#' : invalid character : possibly the result of a macro expansion

Right. Since #include doesn't appear at the start of a line in your code,
it's not a directive, and the # is left and causes syntax errors.

...so that way dont work. i cant do a simple...

#include "files.h"

...with all other includes in that file so im looking for some different
idea and would appreciate any useful help.

Why can't you do that? If you have a problem you want to solve, ask about
that problem. Your attempted solution doesn't work and can't be made to
work. Asking how to change that solution so that it will work won't get
you useful answers. Asking how to solve your original problem may.

[Ben Bacarisse]

".rhavin grobert" <cl***@yahoo.dewrites:

first of all: sorry for perhaps posting something already answered
anywhere, i couldnt find any useful info - define, macro, include and
so on are very poor keywords;-)

my problem:

i want to do something like...

INCLUDE_TYPES(#include);

...that resolves to ...

#include "file1.h"
#include "file2.h"
#include "file3.h"
... and my try was a...

#define INCLUDE_TYPES(Q_L) \
Q_L "file1.h" \
Q_L "file2.h" \
Q_L "file3.h" \

...but my compiler complains about...

'#' : invalid character : possibly the result of a macro expansion

The result of a macro expansion can't be a pre-processing directive --
no matter how much it looks like one. No macro can generate a
#include, #define etc. You can generate those tokens, but they are
not treated as directives.

...so that way dont work. i cant do a simple...

#include "files.h"

...with all other includes in that file so im looking for some
different idea and would appreciate any useful help.

Backup a bit. What problem were you trying to solve?

--
Ben.

[Peter Nilsson]

[e-mail] (Walter Roberson) wrote:

.rhavin grobert <[e-mail]:

my problem:
i want to do something like...
INCLUDE_TYPES(#include);
...that resolves to ...
#include "file1.h"
#include "file2.h"
#include "file3.h"

No macro can expand to a preprocessor directive.

True, but preprocessing directives, including #include,
can expand to macros.

It's possible to do something like what the OP wants
(upto a static limit), but it's questionable as to
whether it's worth doing. Since the OP has admitted
to using C++, it's more likely there are better C++
paradigms to achieve what they really need to do.

But there is a Boost header that does many surprising
pre-processor tricks, and is both C and C++ compatible.

--
Peter