• Lionello Lunesu (25/25) Mar 25 2005 The following behaviour is entirely expected: the auto reference is save...
• =?UTF-8?B?VGhvbWFzIEvDvGhuZQ==?= (44/44) Mar 25 2005 -----BEGIN PGP SIGNED MESSAGE-----
• Walter (7/14) May 08 2005 in

"Lionello Lunesu" <lio lunesu.removethis.com> writes:

The following behaviour is entirely expected: the auto reference is saved in 
a global reference and is invalid after the object leaves the scope.

I wonder if the compiler could have detect this 'error'. Prevent assigning 
an auto reference to another reference? Only allow assignment to variable 
within the scope? Just a thought.

Lionello.

// code
class autoclass
{
public:
  void test() {}  // will not get here
};

static autoclass _b;

void autotest()
{
 auto autoclass _c = new autoclass;
 _b = _c;   // this should be forbidden?
}

int main( char[][]arg )
{
 autotest();
// writefln("%08x",cast(int)cast(void*)_b);
 _b.test();   // "access violation"
 return 1;
}

=?UTF-8?B?VGhvbWFzIEvDvGhuZQ==?= writes:

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Lionello Lunesu wrote:

| The following behaviour is entirely expected: the auto reference
| is saved in  a global reference and is invalid after the object
| leaves the scope.

runs under Windows but segfault's on Linux ...

| I wonder if the compiler could have detect this 'error'. Prevent
| assigning an auto reference to another reference? Only allow
| assignment to variable within the scope? Just a thought.
|
| Lionello.
|
| // code
| class autoclass
| {
| public:
|   void test() {}  // will not get here
| };
|
| static autoclass _b;
|
| void autotest()
| {
|  auto autoclass _c = new autoclass;
|  _b = _c;   // this should be forbidden?
| }
|
| int main( char[][]arg )
| {
|  autotest();
| // writefln("%08x",cast(int)cast(void*)_b);
|  _b.test();   // "access violation"
|  return 1;
| }

Added to DStress as
http://dstress.kuehne.cn/norun/auto_05.d

Thomas

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"Walter" <newshound digitalmars.com> writes:

"Lionello Lunesu" <lio lunesu.removethis.com> wrote in message
news:d2175a$2u8h$1 digitaldaemon.com...
 The following behaviour is entirely expected: the auto reference is saved

in
 a global reference and is invalid after the object leaves the scope.

 I wonder if the compiler could have detect this 'error'. Prevent assigning
 an auto reference to another reference? Only allow assignment to variable
 within the scope? Just a thought.


Added to DStress as
http://dstress.kuehne.cn/norun/auto_05.d



I'm hesitant to have the compiler detect this. There may be legitimate uses
for it, such as instrumenting one's code for debugging purposes. For the
time being, I'll say the usage is legitimate D, although dereferencing the
reference will cause undefined behavior.