# Is allocate a function or subroutine? **URL:** \ **Category:** Help\ **Created:** [February 11, 2022, 10:08pm UTC](https://fortran-lang.discourse.group/t/is-allocate-a-function-or-subroutine/2771 "2022-02-11T22:08:10Z")\ **Posts on this page:** 1\ **Showing post:** 6
**Author:** ![RonShepard](https://avatars.discourse-cdn.com/v4/letter/r/a3d4f5/32.png) [@RonShepard](https://fortran-lang.discourse.group/u/RonShepard)\ **Post date:** [October 28, 2023, 6:06pm UTC](https://fortran-lang.discourse.group/t/is-allocate-a-function-or-subroutine/2771/6 "2023-10-28T18:06:44Z")
It would look screwy if `allocate()` were a subroutine. Instead of something simple and intuitive like ```auto allocate( a(-9:9,-1:1), b(n), c ) ``` the subroutine version would need to look something like ```auto call allocate( a, [-9,9,-1,1], b, [1,n], c, [] ) ``` where the zero-size array `[]` would be required for a scalar allocatable. I’m ignoring the `source=` and `mold=` optional arguments. I think `deallocate()` could be a normal looking subroutine, but that would probably have caused some confusion since it would no longer be symmetrical within the syntax with` allocate()`. The `move_alloc()` intrinsic works pretty much like a normal subroutine. It would be a little difficult to replicate in fortran code because of the arbitrary type+kind+rank aspect, but otherwise it behaves the way a subroutine is expected to behave. It would simplify a lot of my code if `allocate()` had an optional argument to trigger conditional reallocation of an existing array. Say something like ```auto allocate( a(lb:ub), conditional_reallocation=.true. ) ``` If `a(:)` is already allocated with lower bound `lb` and upper bound `ub`, then nothing happens, the array is unchanged. If `a(:)` is already allocated with the correct size but with different bounds, then the bounds are changed but the contents of the array would remain unchanged. If `a(:)` is already allocated but with a different size, then it is deallocated and reallocated with the new size and bounds. All of this can be done now with some trickery, but these common operations should be a standard part of the language. --- _[View the full topic](https://fortran-lang.discourse.group/t/is-allocate-a-function-or-subroutine/2771)._