RE: Bug#527450: indent breaks C code ! (fwd)

"Stephen Anderson" <[email protected]> Wed, 13 May 2009 10:07:01 -0700
Newsgroups gmane.comp.gnu.indent.bugs
Message-ID <8628FE4E7912BF47A96AE7DD7BAC0AAD93C5E4773F@SJEXCHCCR02.corp.ad.broadcom.com>
BTW,  

Replacing the 1 with a variable, "b" in this case, DOES compile and completely changes the behavior which is worse since you there is no compile error.

	a += - -b;

indent transforms it to:

	a += --b;

Which has a different outcome.

int main (int argc, void *argv[])
{
  int a = 20, b = 5;
  a += - -b;
  printf ("a: %d, b: %d\n", a, b);
  return 0;
}
Outputs:
a: 25, b: 5

While
int main (int argc, void *argv[])
{
  int a = 20, b = 5;
  a += --b;
  printf ("a: %d, b: %d\n", a, b);
  return 0;
}
Outputs:
a: 24, b: 4

smanders

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Santiago Vila
Sent: Friday, May 08, 2009 5:52 AM
To: [email protected]
Cc: [email protected]; Xavier Bestel
Subject: Bug#527450: indent breaks C code ! (fwd)

Hello.

I received this from the Debian bug system.
[ Please keep the Cc: lines when replying. Thanks ].

---------- Forwarded message ----------
From: Xavier Bestel <[email protected]>
To: Debian Bug Tracking System <[email protected]>
Date: Thu, 07 May 2009 17:39:32 +0200
Subject: Bug#527450: indent breaks C code !

Package: indent
Version: 2.2.10-1
Severity: important


Hi,

when feeding this line:

	a += - -1;

indent transforms it to:

	a += --1;

which hasn't the same meaning at all (instead of a unary minus on a negative constant, it's a predecrementation of a constant) and in this example isn't even legal C code.

It's quite a serious issue.

Thanks,
	Xav

[...]


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