Intel® Fortran Compiler Classic and Intel® Fortran Compiler Developer Guide and Reference

ID 767251
Date 9/08/2022
Public

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CFI_select_part

C function prototype: Updates a C descriptor for an array section for which each element is a part of the corresponding element of an array.

Syntax
int CFI_select_part(CFI_cdesc_t *result, const CFI_cdesc_t *source,
                    size_t displacement, size_t elem_len);

Formal Parameters:

result

The address of a C descriptor; result->rank must have the same value as source->rank and result->attribute must have the value CFI_attribute_other or CFI_attribute_pointer. If the address specified by result is the value of a C formal parameter that corresponds to a Fortran actual argument or of a C actual argument that corresponds to a Fortran dummy argument, result->attribute must have the value CFI_attribute_pointer. The value of result->type specifies the type of the array section.

source

The address of a C descriptor for a nonallocatable nonpointer array, an allocated allocatable array, or an associated array pointer.

displacement

A value 0 ≤ displacementsource->elem_len − 1, and the sum of the displacement and the size in bytes of an element of the array section must be less than or equal to source->elem_len. The address displacement bytes greater than the value of source->base_addr is the base of the array section and must be appropriately aligned for an object of the type of the array section.

elem_len

A value equal to the storage size in bytes of an element of the array section if result->type specifies a Fortran character type; otherwise, elem_len is ignored.

Description

Successful execution of CFI_select_part updates the base_addr, dim, and elem_len members of the C descriptor with the address result for an array section for which each element is a part of the corresponding element of the array described by the C descriptor with the address source. The part must be a component of a structure, a substring, or the real or imaginary part of a complex value.

If an error is detected, the C descriptor with the address result is not modified.

Result Value

The result is an error indicator.

Example

If source is already the address of a C descriptor for the Fortran array A declared as follows:

TYPE, BIND(C) :: T
REAL(C_DOUBLE) :: X
COMPLEX(C_DOUBLE_COMPLEX) :: Y
END TYPE
TYPE(T) A(100)

then the following code fragment establishes a C descriptor for the array A%Y:

typedef struct {
double x; double _Complex y;
} t;
CFI_CDESC_T(1) component;
CFI_cdesc_t * comp_cdesc = (CFI_cdesc_t *)&component;
CFI_index_t extent[] = { 100 };
(void)CFI_establish(comp_cdesc, NULL, CFI_attribute_other, 
                    CFI_type_double_Complex, 
                    sizeof(double _Complex), 1, extent);
(void)CFI_select_part(comp_cdesc, source, offsetof(t,y), 0);