Is there a way to detect the compiler being used? Namely, is there a
way to have lines of code that are included or ignored by specific
compilers. Or, better, finding certain compiler behaviors to use/
avoid. For example, Visual Studio automatically inserts a
system("PAUSE") statement. Is there any way to detect that VS is being
used and not compile the equivalent line in my program?

Max wrote:
> Is there a way to detect the compiler being used? Namely, is there a
> way to have lines of code that are included or ignored by specific
> compilers. Or, better, finding certain compiler behaviors to use/
> avoid. For example, Visual Studio automatically inserts a
> system("PAUSE") statement. Is there any way to detect that VS is being
> used and not compile the equivalent line in my program?

Detect, no. The language does not mandate the compiler to identify
itself in any way. However, most compilers do offer a few predefined
macros that would you. For example, Visual C++ compiler has the
'MSVC_VER' macro that is defined to match the version of the compiler.
Other compilers do similar stuff, read about their "predefined macros"
in their documentation. IOW RTFM. :-)

V
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On 2008-02-08 22:50, Max wrote:
> For example, Visual Studio automatically inserts a system("PAUSE")
> statement. Is there any way to detect that VS is being used and not
> compile the equivalent line in my program?

Is that something they have started doing recently, because that has
never happened for me.

Or, less sarcastic: No, VS does not insert anything in your code, but if
you use Ctrl+F5 to run your program from the IDE it will be started
using a batch-file which waits for input before terminating after your
program has returned. If you do not want that you can use just F5 to
start the program.

--
Erik Wikström

Max wrote:
> Is there a way to detect the compiler being used? Namely, is there a
> way to have lines of code that are included or ignored by specific
> compilers. Or, better, finding certain compiler behaviors to use/
> avoid. For example, Visual Studio automatically inserts a
> system("PAUSE") statement. Is there any way to detect that VS is being
> used and not compile the equivalent line in my program?

With the Digital Mars C++ compiler,

#if __DMC___
.... insert Digital Mars C++ specific code here ...
#endif

works.

----------------
Walter Bright
http://www.digitalmars.com C, C++, D programming language compilers

Max wrote:
> Is there a way to detect the compiler being used?

There's no *standard* way of detecting it. However, most compilers
will define some precompiler constant(s) to identify themselves. What
these constants are is completely up to the compilers. Also, there's no
guarantee that a newer version of the compiler will not change the name
of that constant. It's all up to the compiler developers. (Since the
standard doesn't specify anything about this, they are free to do as
they like.)

The documentation of some compilers might explicitly mention which
precompiler constants they define for all programs. With some compilers
you can actually print out all the precompiler constants (although
searching for an identifying constant will then be guesswork).

Max wrote:
> Is there a way to detect the compiler being used? Namely, is there a
> way to have lines of code that are included or ignored by specific
> compilers. Or, better, finding certain compiler behaviors to use/
> avoid. For example, Visual Studio automatically inserts a
> system("PAUSE") statement. Is there any way to detect that VS is being
> used and not compile the equivalent line in my program?

As others said, use compiler-specific macros. It is '_MSC_VER' for VC.

You can "reverse-engineer" a list of specific macros for different compilers
from this header file (Trolltech)

http://web.mit.edu/qt_v3.3.3/www/qglobal-h.html

Scroll down to the list of compilers (line 183).

(I couldn't find a nicer list right away, although I'm sure I've seen it somewhere.)

--
Best regards,
Andrey Tarasevich

On Feb 8, 10:50 pm, Max <maxh.is.h...@gmail.com> wrote:
> Is there a way to detect the compiler being used? Namely, is
> there a way to have lines of code that are included or ignored
> by specific compilers. Or, better, finding certain compiler
> behaviors to use/ avoid. For example, Visual Studio
> automatically inserts a system("PAUSE") statement. Is there
> any way to detect that VS is being used and not compile the
> equivalent line in my program?

As others have pointed out, almost every compiler pre-defines
some preprocessor symbols to identify itself, hoping that they
won't conflict with those of any other compiler. But a more
pertinant question, in my mind, would be why you would want to
depend on this. First, of course, most code (99% or more)
should be written so that it doesn't matter. And for that that
does, the symbols are generally defined in a way that only
allows you to use #ifdef, which of course makes the code rapidly
unreadable and unmaintainable. What you really want is 1) one
common symbol which will resolve to the name of a directory, so
you can build up includes to get the right headers *and* system
dependent code, and possibly 2) common symbols which define the
presence or absense of specific features, or how they work (e.g.
things like GB_allowedDirectorySeparators, which can be either
"/" or "\\/"---or maybe something completely different on a
platform I don't currently target). In my experience, the best
way to handle the first is in the command line in the make
file---that needs to be adopted to each compiler anyway, and
adding something like /Dsyst=windows to it doesn't really cause
any additional problems. Or---what I actually use---you can add
a /I option with the directory where you put the system specific
headers. And the second is easily handled once you've done
this; you pick up the defined from a system dependent header.

As for a tool which automatically inserts code which you don't
want, the simple answer is: don't use it.

--
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9 place Sémard, 78210 St.-Cyr-l'École, France, +33 (0)1 30 23 00 34

On 2/8/2008 10:50 PM, Max wrote:
> Is there a way to detect the compiler being used? Namely, is there a
> way to have lines of code that are included or ignored by specific
> compilers. Or, better, finding certain compiler behaviors to use/
> avoid. For example, Visual Studio automatically inserts a
> system("PAUSE") statement. Is there any way to detect that VS is being
> used and not compile the equivalent line in my program?

Maybe this s:

http://predef.sourceforge.net/

Regards,
Stefan
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