包含include语句的宏 [英] macro containing include statement

问题描述

您好，


我想构建一个宏，它有条件包括

另一个源文件。即这样的事情：

#MPIinclude（FileName）（＃include（FileName））/ *另类一个 -

实际上包括MPI源* /


#MPIinclude（FileName）/ *备选方案二 -

a noop * /


这样代码的主体可以包含：


MPIinclude（" path / to / mpi_code / mpi_file.c"）

但是，当前处理宏定义时，我得到

以下错误信息（来自gnu cpp）：


fphs.c：20：32：''＃''后面没有宏参数


，结果代码稍后会在最终编译中失败。


这可能吗？


Joakim

-

Joakim Hove

hove AT ift uib no

[phone]
http://www.ift.uib.no/~hove /

解决方案

Joakim Hove写道：

你好，

我想构建一个宏，它有条件包括另一个源文件。即这样的事情：

#MPIinclude（FileName）（＃include（FileName））/ *替代的一个 -
实际上包括MPI源* /

#MPIinclude （FileName）/ *备选方案二 -
一个noop * /

这样代码的主体可以包含：

MPIinclude（" path / to / mpi_code / mpi_file.c"）

然而，当上面的宏定义预处理时，我得到了以下错误消息（来自gnu cpp）：

fphs.c ：20：32：'''''后面没有一个宏参数

后来生成的代码在最终的编译中失败了。

这可能吗？

Joakim

尝试这样的事情：


#ifdef USE_MPI_SOURCE

#define MPI（文件）"文件"

#else

#define MPI（文件）

#endif


#include MPI（路径/到/ mpi_code / mpi_file.c）


马克

-

<<删除电子邮件的del>>

C预处理器非常简单。

不幸的是，＃define（又名宏）不能包含预处理指令

，如＃define，＃include，＃error，＃pragma ......


看看那里：
http://www.lns.cornell.edu/public/CO...p/cpp_toc.html


" Joakim Hove" <豪** @ ift.uib.no>在留言中写道

news：bj ************* @ aquifer1.fi.uib.no ...

您好，

我想构建一个宏，它有条件包括另一个源文件。即这样的事情：

#MPIinclude（FileName）（＃include（FileName））/ *另类一个 -
实际上包括MPI
来源* /
#MPIinclude （FileName）/ *备选方案二 -
一个noop * /

这样代码的主体可以包含：

MPIinclude（" path / to / mpi_code / mpi_file.c"）

然而，当上面的宏定义预处理时，我得到了以下错误消息（来自gnu cpp）：

fphs.c ：20：32：'''''后面没有一个宏参数

后来生成的代码在最终的编译中失败了。

这可能吗？

Joakim

-
Joakim Hove
hove AT ift uib no
[phone]
< a rel =nofollowhref =http://www.ift.uib.no/~hove/target =_ blank> http://www.ift.uib.no/~hove/

Capstar< ne ** @ deleg.homeip.net>写道：


您好，


感谢您的回答。但不幸的是它不起作用（至少

不用gnu cpp）：

尝试这样的事情：

#ifdef USE_MPI_SOURCE
#define MPI（文件）"文件"
#else
#define MPI（文件）
＃endif


[ ...]

#include MPI（path / to / mpi_code / mpi_file.c）

当定义变量USE_MPI_SOURCE时，我得到：


bash％cpp src_file.c

src_file.c：405：35：file：没有这样的文件或目录


而当它没有定义时我得到：


bash％cpp src_file.c

src_file.c：405：35：#include expect " FILENAME"或者< FILENAME>


这看起来很简单，但它确实包含嵌套的

预处理程序指令，这可能是非法的？


问候


Joakim


-

Joakim Hove

hove AT ift uib no

[phone]
http://www.ift.uib.no/~hove/

Hello,

I would like to construct a macro, which does conditional include of
another source file. i.e. something like this:
#MPIinclude(FileName) (#include (FileName)) /* Alternative one -
actually includes MPI source */

#MPIinclude(FileName) /* Alternative two -
a noop */

So that the body of the code can contain:

MPIinclude("path/to/mpi_code/mpi_file.c")

However, when preprosessing the macro definition above I get the
following error message (from gnu cpp):

fphs.c:20:32: ''#'' is not followed by a macro parameter

and the resulting code later fails in the eventual compilation.

Is this possible?

Joakim
--
Joakim Hove
hove AT ift uib no
[phone]
http://www.ift.uib.no/~hove/

解决方案

Joakim Hove wrote:

Hello,

I would like to construct a macro, which does conditional include of
another source file. i.e. something like this:
#MPIinclude(FileName) (#include (FileName)) /* Alternative one -
actually includes MPI source */

#MPIinclude(FileName) /* Alternative two -
a noop */

So that the body of the code can contain:

MPIinclude("path/to/mpi_code/mpi_file.c")

However, when preprosessing the macro definition above I get the
following error message (from gnu cpp):

fphs.c:20:32: ''#'' is not followed by a macro parameter

and the resulting code later fails in the eventual compilation.

Is this possible?

Joakim

Try something like this:

#ifdef USE_MPI_SOURCE
#define MPI(file) "file"
#else
#define MPI(file)
#endif

#include MPI(path/to/mpi_code/mpi_file.c)

Mark
--
<<Remove the del for email>>

The C preprocessor is really simple.
Unfortunately, a #define (aka macro) can''t contain preprocessing directive
like #define, #include, #error, #pragma...

Have a look there:
http://www.lns.cornell.edu/public/CO...p/cpp_toc.html

"Joakim Hove" <ho**@ift.uib.no> wrote in message
news:bj*************@aquifer1.fi.uib.no...

Hello,

I would like to construct a macro, which does conditional include of
another source file. i.e. something like this:
#MPIinclude(FileName) (#include (FileName)) /* Alternative one -
actually includes MPI source */
#MPIinclude(FileName) /* Alternative two -
a noop */

So that the body of the code can contain:

MPIinclude("path/to/mpi_code/mpi_file.c")

However, when preprosessing the macro definition above I get the
following error message (from gnu cpp):

fphs.c:20:32: ''#'' is not followed by a macro parameter

and the resulting code later fails in the eventual compilation.

Is this possible?

Joakim
--
Joakim Hove
hove AT ift uib no
[phone]
http://www.ift.uib.no/~hove/

Capstar <ne**@deleg.homeip.net> writes:

Hello,

thanks for answering. However unfortunately it does not work (at least
not with gnu cpp):

Try something like this:

#ifdef USE_MPI_SOURCE
#define MPI(file) "file"
#else
#define MPI(file)
#endif
[...]
#include MPI(path/to/mpi_code/mpi_file.c)

When the variable USE_MPI_SOURCE is defined I get:

bash% cpp src_file.c
src_file.c:405:35: file: No such file or directory

whereas when it is not defined I get:

bash% cpp src_file.c
src_file.c:405:35: #include expects "FILENAME" or <FILENAME>

It seemed such a simple construction, but it does contain nested
preprocessor directives, and that is maybe illegal?

Regards

Joakim

--
Joakim Hove
hove AT ift uib no
[phone]
http://www.ift.uib.no/~hove/

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