8.253 SIZEOF — Size in bytes of an expression


SIZEOF(X) calculates the number of bytes of storage the expression X occupies.


GNU extension


Inquiry function



XThe argument shall be of any type, rank or shape.
Return value:

The return value is of type integer and of the system-dependent kind C_SIZE_T (from the ISO_C_BINDING module). Its value is the number of bytes occupied by the argument. If the argument has the POINTER attribute, the number of bytes of the storage area pointed to is returned. If the argument is of a derived type with POINTER or ALLOCATABLE components, the return value does not account for the sizes of the data pointed to by these components. If the argument is polymorphic, the size according to the dynamic type is returned. The argument may not be a procedure or procedure pointer. Note that the code assumes for arrays that those are contiguous; for contiguous arrays, it returns the storage or an array element multiplied by the size of the array.

   integer :: i
   real :: r, s(5)
   print *, (sizeof(s)/sizeof(r) == 5)

The example will print .TRUE. unless you are using a platform where default REAL variables are unusually padded.

See also:

C_SIZEOF — Size in bytes of an expression, STORAGE_SIZE — Storage size in bits