一个通用的swap子程序
本帖最后由 weixing1531 于 2024-4-1 12:39 编辑在Fortran wiki 上看到这个有趣的代码
测试了一下，快速排序慢3倍，堆排序慢35%
module M_swap
private
public swap
contains
subroutine swap(lhs,rhs)
use iso_c_binding
implicit none
class(*),intent(inout) :: lhs, rhs
class(*), allocatable :: temp
! Copy N bytes of SRC to DEST, no aliasing or overlapping allowed.
! extern void *memcpy (void *dest, const void *src, size_t n);
interface
subroutines_memcpy(dest, src, n) bind(C,name='memcpy')
use iso_c_binding
integer(c_intptr_t), value, intent(in) :: dest
integer(c_intptr_t), value, intent(in) :: src
integer(c_size_t), value :: n
end subroutine s_memcpy
end interface
temp=lhs
call s_memcpy(loc(lhs),loc(rhs), storage_size(lhs, kind=c_size_t)/8_c_size_t )
call s_memcpy(loc(rhs), loc(temp), storage_size(rhs, kind=c_size_t)/8_c_size_t )
end subroutine swap
end module M_swap
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