Why would a new[] expression ever invoke a destructor?
From the C++17 standard (draft here), [expr.new]:
If the new-expression creates an object or an array of objects of class type, access and ambiguity control are done for the allocation function, the deallocation function, and the constructor. If the new-expression creates an array of objects of class type, the destructor is potentially invoked.
Why would new invoke a destructor? It's new, after all. It isn't delete.
c++ c++17 new-operator
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From the C++17 standard (draft here), [expr.new]:
If the new-expression creates an object or an array of objects of class type, access and ambiguity control are done for the allocation function, the deallocation function, and the constructor. If the new-expression creates an array of objects of class type, the destructor is potentially invoked.
Why would new invoke a destructor? It's new, after all. It isn't delete.
c++ c++17 new-operator
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Cody Gray♦
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From the C++17 standard (draft here), [expr.new]:
If the new-expression creates an object or an array of objects of class type, access and ambiguity control are done for the allocation function, the deallocation function, and the constructor. If the new-expression creates an array of objects of class type, the destructor is potentially invoked.
Why would new invoke a destructor? It's new, after all. It isn't delete.
c++ c++17 new-operator
edited yesterday
Cody Gray♦
195k35382471
asked yesterday
thbthb
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From the C++17 standard (draft here), [expr.new]:
If the new-expression creates an object or an array of objects of class type, access and ambiguity control are done for the allocation function, the deallocation function, and the constructor. If the new-expression creates an array of objects of class type, the destructor is potentially invoked.
Why would new invoke a destructor? It's new, after all. It isn't delete.
c++ c++17 new-operator
c++ c++17 new-operator
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Cody Gray♦
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thbthb
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Cody Gray♦
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thbthb
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edited yesterday
Cody Gray♦
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edited yesterday
Cody Gray♦
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edited yesterday
Cody Gray♦
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195k35382471
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thbthb
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asked yesterday
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asked yesterday
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8,75932356
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If construction of any object in the buffer throws an exception, the previously constructed objects must be destructed. That requires an available destructor.
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You have not considered the word "potentially" in the quote you have mentioned from the standard.
It means that there is a possibility that invocation of the destructor can happen. And it will happen if construction of any object in the array throws an exception.
Combined with the following quote from [class.dtor]/12.4 which mentions [expr.new], this becomes clear.
In each case, the context of the invocation is the context of the construction of the object. A destructor is also invoked implicitly through use of a delete-expression for a constructed object allocated by a new-expression; the context of the invocation is the delete-expression. [ Note: An array of class type contains several subobjects for each of which the destructor is invoked. — end note ] A destructor can also be invoked explicitly. A destructor is potentially invoked if it is invoked or as specified in
[expr.new],[class.base.init], and[except.throw]. A program is ill-formed if a destructor that is potentially invoked is deleted or not accessible from the context of the invocation.
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2 Answers
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2 Answers
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If construction of any object in the buffer throws an exception, the previously constructed objects must be destructed. That requires an available destructor.
edited yesterday
Sombrero Chicken
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StoryTellerStoryTeller
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If construction of any object in the buffer throws an exception, the previously constructed objects must be destructed. That requires an available destructor.
edited yesterday
Sombrero Chicken
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answered yesterday
StoryTellerStoryTeller
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If construction of any object in the buffer throws an exception, the previously constructed objects must be destructed. That requires an available destructor.
edited yesterday
Sombrero Chicken
24.4k33281
answered yesterday
StoryTellerStoryTeller
103k12216280
If construction of any object in the buffer throws an exception, the previously constructed objects must be destructed. That requires an available destructor.
edited yesterday
Sombrero Chicken
24.4k33281
answered yesterday
StoryTellerStoryTeller
103k12216280
edited yesterday
Sombrero Chicken
24.4k33281
edited yesterday
Sombrero Chicken
24.4k33281
edited yesterday
Sombrero Chicken
24.4k33281
24.4k33281
answered yesterday
StoryTellerStoryTeller
103k12216280
answered yesterday
StoryTellerStoryTeller
103k12216280
answered yesterday
StoryTellerStoryTeller
103k12216280
103k12216280
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add a comment |
You have not considered the word "potentially" in the quote you have mentioned from the standard.
It means that there is a possibility that invocation of the destructor can happen. And it will happen if construction of any object in the array throws an exception.
Combined with the following quote from [class.dtor]/12.4 which mentions [expr.new], this becomes clear.
In each case, the context of the invocation is the context of the construction of the object. A destructor is also invoked implicitly through use of a delete-expression for a constructed object allocated by a new-expression; the context of the invocation is the delete-expression. [ Note: An array of class type contains several subobjects for each of which the destructor is invoked. — end note ] A destructor can also be invoked explicitly. A destructor is potentially invoked if it is invoked or as specified in
[expr.new],[class.base.init], and[except.throw]. A program is ill-formed if a destructor that is potentially invoked is deleted or not accessible from the context of the invocation.
answered yesterday
P.WP.W
17.1k41555
add a comment |
You have not considered the word "potentially" in the quote you have mentioned from the standard.
It means that there is a possibility that invocation of the destructor can happen. And it will happen if construction of any object in the array throws an exception.
Combined with the following quote from [class.dtor]/12.4 which mentions [expr.new], this becomes clear.
In each case, the context of the invocation is the context of the construction of the object. A destructor is also invoked implicitly through use of a delete-expression for a constructed object allocated by a new-expression; the context of the invocation is the delete-expression. [ Note: An array of class type contains several subobjects for each of which the destructor is invoked. — end note ] A destructor can also be invoked explicitly. A destructor is potentially invoked if it is invoked or as specified in
[expr.new],[class.base.init], and[except.throw]. A program is ill-formed if a destructor that is potentially invoked is deleted or not accessible from the context of the invocation.
answered yesterday
P.WP.W
17.1k41555
add a comment |
You have not considered the word "potentially" in the quote you have mentioned from the standard.
It means that there is a possibility that invocation of the destructor can happen. And it will happen if construction of any object in the array throws an exception.
Combined with the following quote from [class.dtor]/12.4 which mentions [expr.new], this becomes clear.
In each case, the context of the invocation is the context of the construction of the object. A destructor is also invoked implicitly through use of a delete-expression for a constructed object allocated by a new-expression; the context of the invocation is the delete-expression. [ Note: An array of class type contains several subobjects for each of which the destructor is invoked. — end note ] A destructor can also be invoked explicitly. A destructor is potentially invoked if it is invoked or as specified in
[expr.new],[class.base.init], and[except.throw]. A program is ill-formed if a destructor that is potentially invoked is deleted or not accessible from the context of the invocation.
answered yesterday
P.WP.W
17.1k41555
You have not considered the word "potentially" in the quote you have mentioned from the standard.
It means that there is a possibility that invocation of the destructor can happen. And it will happen if construction of any object in the array throws an exception.
Combined with the following quote from [class.dtor]/12.4 which mentions [expr.new], this becomes clear.
In each case, the context of the invocation is the context of the construction of the object. A destructor is also invoked implicitly through use of a delete-expression for a constructed object allocated by a new-expression; the context of the invocation is the delete-expression. [ Note: An array of class type contains several subobjects for each of which the destructor is invoked. — end note ] A destructor can also be invoked explicitly. A destructor is potentially invoked if it is invoked or as specified in
[expr.new],[class.base.init], and[except.throw]. A program is ill-formed if a destructor that is potentially invoked is deleted or not accessible from the context of the invocation.
answered yesterday
P.WP.W
17.1k41555
answered yesterday
P.WP.W
17.1k41555
answered yesterday
P.WP.W
17.1k41555
answered yesterday
P.WP.W
17.1k41555
17.1k41555
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add a comment |
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