Is delete *p an alternative to delete [] p?
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The following code is from the Microsoft Documentation
int (**p) () = new (int (*[7]) ());
delete *p;
I think that delete p
should be used here instead.
Is delete *p
the same as delete p
?
c++ arrays
add a comment |
The following code is from the Microsoft Documentation
int (**p) () = new (int (*[7]) ());
delete *p;
I think that delete p
should be used here instead.
Is delete *p
the same as delete p
?
c++ arrays
4
delete *p
differs fromdelete p
.
– Jarod42
9 hours ago
You're right. They're not the same.
– Cruz Jean
9 hours ago
1
typedef
would make thing clearer.
– Jarod42
9 hours ago
Anywayp[0]
is not initialized. They have typo.
– Jarod42
9 hours ago
delete
what wasnew
ed anddelete
what wasnew
ed. Though in modern code you should avoid most uses ofnew
, it's no longer the preferred way of dynamically creating objects. Seestd::make_unique
andstd::make_shared
instead or use a standard container.
– François Andrieux
9 hours ago
add a comment |
The following code is from the Microsoft Documentation
int (**p) () = new (int (*[7]) ());
delete *p;
I think that delete p
should be used here instead.
Is delete *p
the same as delete p
?
c++ arrays
The following code is from the Microsoft Documentation
int (**p) () = new (int (*[7]) ());
delete *p;
I think that delete p
should be used here instead.
Is delete *p
the same as delete p
?
c++ arrays
c++ arrays
edited 9 hours ago
Guillaume Racicot
16.1k53871
16.1k53871
asked 9 hours ago
xiaokaoyxiaokaoy
7152719
7152719
4
delete *p
differs fromdelete p
.
– Jarod42
9 hours ago
You're right. They're not the same.
– Cruz Jean
9 hours ago
1
typedef
would make thing clearer.
– Jarod42
9 hours ago
Anywayp[0]
is not initialized. They have typo.
– Jarod42
9 hours ago
delete
what wasnew
ed anddelete
what wasnew
ed. Though in modern code you should avoid most uses ofnew
, it's no longer the preferred way of dynamically creating objects. Seestd::make_unique
andstd::make_shared
instead or use a standard container.
– François Andrieux
9 hours ago
add a comment |
4
delete *p
differs fromdelete p
.
– Jarod42
9 hours ago
You're right. They're not the same.
– Cruz Jean
9 hours ago
1
typedef
would make thing clearer.
– Jarod42
9 hours ago
Anywayp[0]
is not initialized. They have typo.
– Jarod42
9 hours ago
delete
what wasnew
ed anddelete
what wasnew
ed. Though in modern code you should avoid most uses ofnew
, it's no longer the preferred way of dynamically creating objects. Seestd::make_unique
andstd::make_shared
instead or use a standard container.
– François Andrieux
9 hours ago
4
4
delete *p
differs from delete p
.– Jarod42
9 hours ago
delete *p
differs from delete p
.– Jarod42
9 hours ago
You're right. They're not the same.
– Cruz Jean
9 hours ago
You're right. They're not the same.
– Cruz Jean
9 hours ago
1
1
typedef
would make thing clearer.– Jarod42
9 hours ago
typedef
would make thing clearer.– Jarod42
9 hours ago
Anyway
p[0]
is not initialized. They have typo.– Jarod42
9 hours ago
Anyway
p[0]
is not initialized. They have typo.– Jarod42
9 hours ago
delete
what was new
ed and delete
what was new
ed. Though in modern code you should avoid most uses of new
, it's no longer the preferred way of dynamically creating objects. See std::make_unique
and std::make_shared
instead or use a standard container.– François Andrieux
9 hours ago
delete
what was new
ed and delete
what was new
ed. Though in modern code you should avoid most uses of new
, it's no longer the preferred way of dynamically creating objects. See std::make_unique
and std::make_shared
instead or use a standard container.– François Andrieux
9 hours ago
add a comment |
2 Answers
2
active
oldest
votes
That code is invalid C++, because only pointers-to-objects can be deleted. *p
has type int (*)()
, which is a function pointer, not a pointer to an object.
Even MSVC itself does not compile it, even in permissive mode:
error C2541: 'delete': cannot delete objects that are not pointers
They should have used delete
instead.
In what context one may need to dynamically allocate pointers to functions?
– Ayxan
9 hours ago
@Ayxan That would be another question, but for instance you may want to have a list of arbitrary operations to execute.
– Acorn
8 hours ago
@Ayxan I have quickly posted it here: stackoverflow.com/q/55524710/9305398
– Acorn
8 hours ago
Even though this is specific to MSVC, g++ gives the following similar error when trying to compile:error: cannot delete expression of type 'int (*)()'
.. seems odd that MS would have missed something that simple in their docs :/
– txtechhelp
7 hours ago
add a comment |
- This code specifically has a different issue as it tries to delete an inner element of an array so it will not compile. It would compile if you wrote delete p and not delete *p.
- You can use simple delete on an object allocated by new if It is an array of primitive types. Bad practice, ugly, yes. But not a mistake.
- The difference between delete and delete is that the former also calls destructors. For primitive types, however, it will call simple delete to free the memory internally anyway.
- Again, even if it works, you should avoid mixing operator types.
delete
calls destructors...
– Acorn
8 hours ago
Mixing operators is undefined behavior.
– Ayxan
8 hours ago
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
That code is invalid C++, because only pointers-to-objects can be deleted. *p
has type int (*)()
, which is a function pointer, not a pointer to an object.
Even MSVC itself does not compile it, even in permissive mode:
error C2541: 'delete': cannot delete objects that are not pointers
They should have used delete
instead.
In what context one may need to dynamically allocate pointers to functions?
– Ayxan
9 hours ago
@Ayxan That would be another question, but for instance you may want to have a list of arbitrary operations to execute.
– Acorn
8 hours ago
@Ayxan I have quickly posted it here: stackoverflow.com/q/55524710/9305398
– Acorn
8 hours ago
Even though this is specific to MSVC, g++ gives the following similar error when trying to compile:error: cannot delete expression of type 'int (*)()'
.. seems odd that MS would have missed something that simple in their docs :/
– txtechhelp
7 hours ago
add a comment |
That code is invalid C++, because only pointers-to-objects can be deleted. *p
has type int (*)()
, which is a function pointer, not a pointer to an object.
Even MSVC itself does not compile it, even in permissive mode:
error C2541: 'delete': cannot delete objects that are not pointers
They should have used delete
instead.
In what context one may need to dynamically allocate pointers to functions?
– Ayxan
9 hours ago
@Ayxan That would be another question, but for instance you may want to have a list of arbitrary operations to execute.
– Acorn
8 hours ago
@Ayxan I have quickly posted it here: stackoverflow.com/q/55524710/9305398
– Acorn
8 hours ago
Even though this is specific to MSVC, g++ gives the following similar error when trying to compile:error: cannot delete expression of type 'int (*)()'
.. seems odd that MS would have missed something that simple in their docs :/
– txtechhelp
7 hours ago
add a comment |
That code is invalid C++, because only pointers-to-objects can be deleted. *p
has type int (*)()
, which is a function pointer, not a pointer to an object.
Even MSVC itself does not compile it, even in permissive mode:
error C2541: 'delete': cannot delete objects that are not pointers
They should have used delete
instead.
That code is invalid C++, because only pointers-to-objects can be deleted. *p
has type int (*)()
, which is a function pointer, not a pointer to an object.
Even MSVC itself does not compile it, even in permissive mode:
error C2541: 'delete': cannot delete objects that are not pointers
They should have used delete
instead.
edited 9 hours ago
answered 9 hours ago
AcornAcorn
6,20111341
6,20111341
In what context one may need to dynamically allocate pointers to functions?
– Ayxan
9 hours ago
@Ayxan That would be another question, but for instance you may want to have a list of arbitrary operations to execute.
– Acorn
8 hours ago
@Ayxan I have quickly posted it here: stackoverflow.com/q/55524710/9305398
– Acorn
8 hours ago
Even though this is specific to MSVC, g++ gives the following similar error when trying to compile:error: cannot delete expression of type 'int (*)()'
.. seems odd that MS would have missed something that simple in their docs :/
– txtechhelp
7 hours ago
add a comment |
In what context one may need to dynamically allocate pointers to functions?
– Ayxan
9 hours ago
@Ayxan That would be another question, but for instance you may want to have a list of arbitrary operations to execute.
– Acorn
8 hours ago
@Ayxan I have quickly posted it here: stackoverflow.com/q/55524710/9305398
– Acorn
8 hours ago
Even though this is specific to MSVC, g++ gives the following similar error when trying to compile:error: cannot delete expression of type 'int (*)()'
.. seems odd that MS would have missed something that simple in their docs :/
– txtechhelp
7 hours ago
In what context one may need to dynamically allocate pointers to functions?
– Ayxan
9 hours ago
In what context one may need to dynamically allocate pointers to functions?
– Ayxan
9 hours ago
@Ayxan That would be another question, but for instance you may want to have a list of arbitrary operations to execute.
– Acorn
8 hours ago
@Ayxan That would be another question, but for instance you may want to have a list of arbitrary operations to execute.
– Acorn
8 hours ago
@Ayxan I have quickly posted it here: stackoverflow.com/q/55524710/9305398
– Acorn
8 hours ago
@Ayxan I have quickly posted it here: stackoverflow.com/q/55524710/9305398
– Acorn
8 hours ago
Even though this is specific to MSVC, g++ gives the following similar error when trying to compile:
error: cannot delete expression of type 'int (*)()'
.. seems odd that MS would have missed something that simple in their docs :/– txtechhelp
7 hours ago
Even though this is specific to MSVC, g++ gives the following similar error when trying to compile:
error: cannot delete expression of type 'int (*)()'
.. seems odd that MS would have missed something that simple in their docs :/– txtechhelp
7 hours ago
add a comment |
- This code specifically has a different issue as it tries to delete an inner element of an array so it will not compile. It would compile if you wrote delete p and not delete *p.
- You can use simple delete on an object allocated by new if It is an array of primitive types. Bad practice, ugly, yes. But not a mistake.
- The difference between delete and delete is that the former also calls destructors. For primitive types, however, it will call simple delete to free the memory internally anyway.
- Again, even if it works, you should avoid mixing operator types.
delete
calls destructors...
– Acorn
8 hours ago
Mixing operators is undefined behavior.
– Ayxan
8 hours ago
add a comment |
- This code specifically has a different issue as it tries to delete an inner element of an array so it will not compile. It would compile if you wrote delete p and not delete *p.
- You can use simple delete on an object allocated by new if It is an array of primitive types. Bad practice, ugly, yes. But not a mistake.
- The difference between delete and delete is that the former also calls destructors. For primitive types, however, it will call simple delete to free the memory internally anyway.
- Again, even if it works, you should avoid mixing operator types.
delete
calls destructors...
– Acorn
8 hours ago
Mixing operators is undefined behavior.
– Ayxan
8 hours ago
add a comment |
- This code specifically has a different issue as it tries to delete an inner element of an array so it will not compile. It would compile if you wrote delete p and not delete *p.
- You can use simple delete on an object allocated by new if It is an array of primitive types. Bad practice, ugly, yes. But not a mistake.
- The difference between delete and delete is that the former also calls destructors. For primitive types, however, it will call simple delete to free the memory internally anyway.
- Again, even if it works, you should avoid mixing operator types.
- This code specifically has a different issue as it tries to delete an inner element of an array so it will not compile. It would compile if you wrote delete p and not delete *p.
- You can use simple delete on an object allocated by new if It is an array of primitive types. Bad practice, ugly, yes. But not a mistake.
- The difference between delete and delete is that the former also calls destructors. For primitive types, however, it will call simple delete to free the memory internally anyway.
- Again, even if it works, you should avoid mixing operator types.
answered 8 hours ago
Yuri NudelmanYuri Nudelman
1,4061614
1,4061614
delete
calls destructors...
– Acorn
8 hours ago
Mixing operators is undefined behavior.
– Ayxan
8 hours ago
add a comment |
delete
calls destructors...
– Acorn
8 hours ago
Mixing operators is undefined behavior.
– Ayxan
8 hours ago
delete
calls destructors...– Acorn
8 hours ago
delete
calls destructors...– Acorn
8 hours ago
Mixing operators is undefined behavior.
– Ayxan
8 hours ago
Mixing operators is undefined behavior.
– Ayxan
8 hours ago
add a comment |
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4
delete *p
differs fromdelete p
.– Jarod42
9 hours ago
You're right. They're not the same.
– Cruz Jean
9 hours ago
1
typedef
would make thing clearer.– Jarod42
9 hours ago
Anyway
p[0]
is not initialized. They have typo.– Jarod42
9 hours ago
delete
what wasnew
ed anddelete
what wasnew
ed. Though in modern code you should avoid most uses ofnew
, it's no longer the preferred way of dynamically creating objects. Seestd::make_unique
andstd::make_shared
instead or use a standard container.– François Andrieux
9 hours ago