XL Fortran Enterprise Edition for AIX : User's Guide - IBM

Table 25. Escape Sequences for Character Strings (continued)
Escape
Meaning
\x x, where x is any other character (the backslash is ignored)
If you do not want the backslash interpreted as an escape character within strings,
you can compile with the -qnoescape option.
Passing Arrays between Languages
Fortran stores array elements in ascending storage units in column-major order. C
and Pascal store array elements in row-major order. Fortran and Pascal array
indexes start at 1, while C array indexes start at 0.
The following example shows how a two-dimensional array that is declared by
A(3,2) is stored in Fortran, C, and Pascal:
Table 26. Corresponding Array Layouts for Fortran, C, and Pascal. The Fortran array
reference A(X,Y,Z) can be expressed in C as a[Z-1][Y-1][X-1] and in Pascal as A[Z,Y,X].
Keep in mind that although C passes individual scalar array elements by value, it passes
arrays by reference.
Fortran Element
Name
C Element Name
Lowest storage unit A(1,1) A[0][0] A[1,1]
A(2,1) A[0][1] A[1,2]
A(3,1) A[1][0] A[2,1]
A(1,2) A[1][1] A[2,2]
A(2,2) A[2][0] A[3,1]
Highest storage unit A(3,2) A[2][1] A[3,2]
Pascal Element
Name
To pass all or part of a Fortran array to another language, you can use Fortran
90/Fortran 95 array notation:
REAL, DIMENSION(4,8) :: A, B(10)
! Pass an entire 4 x 8 array.
CALL CFUNC( A )
! Pass only the upper-left quadrant of the array.
CALL CFUNC( A(1:2,1:4) )
! Pass an array consisting of every third element of A.
CALL CFUNC( A(1:4:3,1:8) )
! Pass a 1-dimensional array consisting of elements 1, 2, and 4 of B.
CALL CFUNC( B( (/1,2,4/) ) )
Where necessary, the Fortran program constructs a temporary array and copies all
the elements into contiguous storage. In all cases, the C routine needs to account
for the column-major layout of the array.
Any array section or noncontiguous array is passed as the address of a contiguous
temporary unless an explicit interface exists where the corresponding dummy
argument is declared as an assumed-shape array or a pointer. To avoid the creation
of array descriptors (which are not supported for interlanguage calls) when calling
non-Fortran procedures with array arguments, either do not give the non-Fortran
procedures any explicit interface, or do not declare the corresponding dummy
arguments as assumed-shape or pointers in the interface:
352 XL Fortran Enterprise Edition for AIX : User’s Guide