6.1 ALLOCATE Statement

The ALLOCATE statement dynamically creates storage for allocatable arrays and pointer targets. The storage space allocated is uninitialized.

The ALLOCATE statement takes the following form:

ALLOCATE (object [(s-spec[, s-spec...])] [, object[(s-spec[, s-spec...])]]...[, STAT=sv])

object
Is the object to be allocated. It is a variable name or structure component, and must be a pointer or allocatable array. The object can be of type character with zero length.

s-spec
Is a shape specification in the form [lower-bound:]upper-bound. Each bound must be a scalar integer expression. The number of shape specifications must be the same as the rank of the object.

sv
Is a scalar integer variable in which the status of the allocation is stored.

Rules and Behavior

A bound in s-spec must not be an expression containing an array inquiry function whose argument is any allocatable object in the same ALLOCATE statement; for example, the following is not permitted:

INTEGER ERR
INTEGER, ALLOCATABLE :: A(:), B(:)
...
ALLOCATE(A(10:25), B(SIZE(A)), STAT=ERR)  ! A is invalid as an argument
                                          !   to function SIZE

If a STAT variable is specified, it must not be allocated in the ALLOCATE statement in which it appears. If the allocation is successful, the variable is set to zero. If the allocation is not successful, an error condition occurs, and the variable is set to a positive integer value (representing the run-time error). If no STAT variable is specified and an error condition occurs, program execution terminates.

Examples

The following is an example of the ALLOCATE statement:

INTEGER J, N, ALLOC_ERR
REAL, ALLOCATABLE :: A(:), B(:,:)
...
ALLOCATE(A(0:80), B(-3:J+1, N), STAT = ALLOC_ERR)

For More Information:

• On allocatable arrays, see Section 5.2.
  
  
• On pointers, see Section 5.15.
  
  
• On run-time error messages, see your user manual or online documentation.