Why aren't sync.WaitGroup, sync.Mutex reference types like channel, slices?
If Waitgroups and Mutex always needs to be passed by reference always, can't we make it a reference type (forbid the use of them as pass by value)? I mean is there any use case where we need to use them pass by value?
go concurrency edited Nov 17 '18 at 18:30
Flimzy
37.4k96496
asked Nov 17 '18 at 8:27
Abdul Rahman K
555416
add a comment |
If Waitgroups and Mutex always needs to be passed by reference always, can't we make it a reference type (forbid the use of them as pass by value)? I mean is there any use case where we need to use them pass by value?
go concurrency edited Nov 17 '18 at 18:30
Flimzy
37.4k96496
asked Nov 17 '18 at 8:27
Abdul Rahman K
555416
add a comment |
If Waitgroups and Mutex always needs to be passed by reference always, can't we make it a reference type (forbid the use of them as pass by value)? I mean is there any use case where we need to use them pass by value?
go concurrency edited Nov 17 '18 at 18:30
Flimzy
37.4k96496
asked Nov 17 '18 at 8:27
Abdul Rahman K
555416
If Waitgroups and Mutex always needs to be passed by reference always, can't we make it a reference type (forbid the use of them as pass by value)? I mean is there any use case where we need to use them pass by value?
go concurrency go concurrency edited Nov 17 '18 at 18:30
Flimzy
37.4k96496
asked Nov 17 '18 at 8:27
Abdul Rahman K
555416
edited Nov 17 '18 at 18:30
Flimzy
37.4k96496
asked Nov 17 '18 at 8:27
Abdul Rahman K
555416
edited Nov 17 '18 at 18:30
Flimzy
37.4k96496
edited Nov 17 '18 at 18:30
Flimzy
37.4k96496
edited Nov 17 '18 at 18:30
Flimzy
37.4k96496
37.4k96496
asked Nov 17 '18 at 8:27
Abdul Rahman K
555416
asked Nov 17 '18 at 8:27
Abdul Rahman K
555416
asked Nov 17 '18 at 8:27
Abdul Rahman K
555416
555416
add a comment |
add a comment |
1 Answer
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When you pass any argument as value, the value will get copied. Any modification these arguments will be local the the func. When the func exits those changes will be gone.
In case of a WaitGroup or Mutex you do not want this, as you want to share the state. If all modifications were local, you could not sync anything, as you would have many different copies with different states.
One valid case could be that you want to copy a WaitGroup or Mutex, but that would be very implicit code and hard for another developer to understand/maintain.
answered Nov 17 '18 at 8:34
mbuechmann
2,80121224
I totally agree with what you say. Does it make sense to forbid pass by value of waitgroups and mutex?
– Abdul Rahman K
Nov 17 '18 at 8:37
Hi. I just extended my answer. Hope that helps.
– mbuechmann
Nov 17 '18 at 8:38
Still there is this question of when would we want to copy a WaitGroup/ Mutex ?
– Abdul Rahman K
Nov 17 '18 at 8:40
That depends on your program or what you want to achieve. But I think it is always better to explicitly create a new one.
– mbuechmann
Nov 17 '18 at 8:42
Exactly the point, It's always better to create a new one. So can we restrict the pass by value ability of them?
– Abdul Rahman K
Nov 17 '18 at 8:45
|
show 2 more comments
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1 Answer
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active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
When you pass any argument as value, the value will get copied. Any modification these arguments will be local the the func. When the func exits those changes will be gone.
In case of a WaitGroup or Mutex you do not want this, as you want to share the state. If all modifications were local, you could not sync anything, as you would have many different copies with different states.
One valid case could be that you want to copy a WaitGroup or Mutex, but that would be very implicit code and hard for another developer to understand/maintain.
answered Nov 17 '18 at 8:34
mbuechmann
2,80121224
I totally agree with what you say. Does it make sense to forbid pass by value of waitgroups and mutex?
– Abdul Rahman K
Nov 17 '18 at 8:37
Hi. I just extended my answer. Hope that helps.
– mbuechmann
Nov 17 '18 at 8:38
Still there is this question of when would we want to copy a WaitGroup/ Mutex ?
– Abdul Rahman K
Nov 17 '18 at 8:40
That depends on your program or what you want to achieve. But I think it is always better to explicitly create a new one.
– mbuechmann
Nov 17 '18 at 8:42
Exactly the point, It's always better to create a new one. So can we restrict the pass by value ability of them?
– Abdul Rahman K
Nov 17 '18 at 8:45
|
show 2 more comments
When you pass any argument as value, the value will get copied. Any modification these arguments will be local the the func. When the func exits those changes will be gone.
In case of a WaitGroup or Mutex you do not want this, as you want to share the state. If all modifications were local, you could not sync anything, as you would have many different copies with different states.
One valid case could be that you want to copy a WaitGroup or Mutex, but that would be very implicit code and hard for another developer to understand/maintain.
answered Nov 17 '18 at 8:34
mbuechmann
2,80121224
I totally agree with what you say. Does it make sense to forbid pass by value of waitgroups and mutex?
– Abdul Rahman K
Nov 17 '18 at 8:37
Hi. I just extended my answer. Hope that helps.
– mbuechmann
Nov 17 '18 at 8:38
Still there is this question of when would we want to copy a WaitGroup/ Mutex ?
– Abdul Rahman K
Nov 17 '18 at 8:40
That depends on your program or what you want to achieve. But I think it is always better to explicitly create a new one.
– mbuechmann
Nov 17 '18 at 8:42
Exactly the point, It's always better to create a new one. So can we restrict the pass by value ability of them?
– Abdul Rahman K
Nov 17 '18 at 8:45
|
show 2 more comments
When you pass any argument as value, the value will get copied. Any modification these arguments will be local the the func. When the func exits those changes will be gone.
In case of a WaitGroup or Mutex you do not want this, as you want to share the state. If all modifications were local, you could not sync anything, as you would have many different copies with different states.
One valid case could be that you want to copy a WaitGroup or Mutex, but that would be very implicit code and hard for another developer to understand/maintain.
answered Nov 17 '18 at 8:34
mbuechmann
2,80121224
When you pass any argument as value, the value will get copied. Any modification these arguments will be local the the func. When the func exits those changes will be gone.
In case of a WaitGroup or Mutex you do not want this, as you want to share the state. If all modifications were local, you could not sync anything, as you would have many different copies with different states.
One valid case could be that you want to copy a WaitGroup or Mutex, but that would be very implicit code and hard for another developer to understand/maintain.
answered Nov 17 '18 at 8:34
mbuechmann
2,80121224
edited Nov 17 '18 at 8:38
answered Nov 17 '18 at 8:34
mbuechmann
2,80121224
answered Nov 17 '18 at 8:34
mbuechmann
2,80121224
answered Nov 17 '18 at 8:34
mbuechmann
2,80121224
2,80121224
I totally agree with what you say. Does it make sense to forbid pass by value of waitgroups and mutex?
– Abdul Rahman K
Nov 17 '18 at 8:37
Hi. I just extended my answer. Hope that helps.
– mbuechmann
Nov 17 '18 at 8:38
Still there is this question of when would we want to copy a WaitGroup/ Mutex ?
– Abdul Rahman K
Nov 17 '18 at 8:40
That depends on your program or what you want to achieve. But I think it is always better to explicitly create a new one.
– mbuechmann
Nov 17 '18 at 8:42
Exactly the point, It's always better to create a new one. So can we restrict the pass by value ability of them?
– Abdul Rahman K
Nov 17 '18 at 8:45
|
show 2 more comments
I totally agree with what you say. Does it make sense to forbid pass by value of waitgroups and mutex?
– Abdul Rahman K
Nov 17 '18 at 8:37
Hi. I just extended my answer. Hope that helps.
– mbuechmann
Nov 17 '18 at 8:38
Still there is this question of when would we want to copy a WaitGroup/ Mutex ?
– Abdul Rahman K
Nov 17 '18 at 8:40
That depends on your program or what you want to achieve. But I think it is always better to explicitly create a new one.
– mbuechmann
Nov 17 '18 at 8:42
Exactly the point, It's always better to create a new one. So can we restrict the pass by value ability of them?
– Abdul Rahman K
Nov 17 '18 at 8:45
I totally agree with what you say. Does it make sense to forbid pass by value of waitgroups and mutex?
– Abdul Rahman K
Nov 17 '18 at 8:37
I totally agree with what you say. Does it make sense to forbid pass by value of waitgroups and mutex?
– Abdul Rahman K
Nov 17 '18 at 8:37
Hi. I just extended my answer. Hope that helps.
– mbuechmann
Nov 17 '18 at 8:38
Hi. I just extended my answer. Hope that helps.
– mbuechmann
Nov 17 '18 at 8:38
Still there is this question of when would we want to copy a WaitGroup/ Mutex ?
– Abdul Rahman K
Nov 17 '18 at 8:40
Still there is this question of when would we want to copy a WaitGroup/ Mutex ?
– Abdul Rahman K
Nov 17 '18 at 8:40
That depends on your program or what you want to achieve. But I think it is always better to explicitly create a new one.
– mbuechmann
Nov 17 '18 at 8:42
That depends on your program or what you want to achieve. But I think it is always better to explicitly create a new one.
– mbuechmann
Nov 17 '18 at 8:42
Exactly the point, It's always better to create a new one. So can we restrict the pass by value ability of them?
– Abdul Rahman K
Nov 17 '18 at 8:45
Exactly the point, It's always better to create a new one. So can we restrict the pass by value ability of them?
– Abdul Rahman K
Nov 17 '18 at 8:45
|
show 2 more comments
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