Question regarding C++ and inline assembler...

Question regarding C++ and inline assembler...

[Scott Bambrough]

The following code fragment generates a error when compiled as C++ code, but not
as C code.

int main (int argc, char **argv)
{
  __asm__ ("mov r0, #0", ::: "r0");	/* error in C++, not C */
  __asm__ ("mov r0, #0", : : : "r0");   /* fine in C and C++ */
}

Shouldn't the C++ compiler be able to cope with no whitespace between the colons
when compiling the inline assembler?

Scott

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Re: Question regarding C++ and inline assembler...

[Alexandre Oliva]

On Jan 27, 2000, Scott Bambrough <scottb@netwinder.org> wrote:

> Shouldn't the C++ compiler be able to cope with no whitespace
> between the colons when compiling the inline assembler?

Well, it could do it, but `::' is a C++ token, totally different from
`: :'.  So it would be best not to rely on g++'s special-casing of
`::' within asm statements.  Anyway, g++ accepts `>>' as `> >' when
`>' is used as a template bracket, so this might be considered
precedent.  I doubt a patch that implemented this feature would be
rejected.

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Re: Question regarding C++ and inline assembler...

[David Young]

> Anyway, g++ accepts `>>' as `> >' when
> `>' is used as a template bracket

That could be because >> pattern being the ANSI shift-right is defined to  
accept white space and comments within the token, so

>>
>  >
> /*obnoxious comment*/ >

are all tokenized to the same >> token

-- from my understanding

whereas :: is not part of ANSI-C, thus there does not have to be such  
ignoring of white and comments by design.

Please correct me if I'm wrong.

Thanks A Bunch! David Young; VVI-DCS
dyoung@vvi.com

Re: Question regarding C++ and inline assembler...

[Andreas Schwab]

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David Young <dyoung@vviuh221.vvi.com> writes:

|> > Anyway, g++ accepts `>>' as `> >' when
|> > `>' is used as a template bracket
|> 
|> That could be because >> pattern being the ANSI shift-right is defined to  
|> accept white space and comments within the token, so
|> 
|> >>
|> >  >
|> > /*obnoxious comment*/ >
|> 
|> are all tokenized to the same >> token

This is wrong.  There must not be any whitespace inside tokens (except
string and character literals, of course).

Andreas.

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