HP UX Fortran Software Example 25 Example 8-5 passarray.f90, Example 26 Example 8-6 getarray.c

Example 25 Example 8-5 pass_array.f90

PROGRAM main ! This program initializes a multi-dimensional array,

!displays its contents, then passes it to a C function,

!which displays its contents. The C function has the

!following declaration prototype:

!

! void get_array(int a[4][2]); !

!Note that the dimensions are declared in reverse order

!in C from the way they are declared in Fortran. INTEGER, DIMENSION(2,4) :: my_array = &

RESHAPE(SOURCE = (/1,2,3,4,5,6,7,8/), SHAPE = (/2,4/)) PRINT *, 'Here is how Fortran stores the array:' DO i = 1, 4

DO j = 1, 2

PRINT 10, j, i, my_array(j,i)

END DO

END DO

!There’s no need to use the %VAL or %REF built-in functions

!because both C and Fortran pass arrays by reference.

CALL get_array(my_array)

10 FORMAT(‘my_array(', I1, ',', I1, ') =', I2) END PROGRAM main

Below is the source file for a HP Fortran program that calls a C function, passing a two-dimensional array of integers.

The following is the source file for the C function.

Example 26 Example 8-6 get_array.c

#include <stdio.h>

/* get_array: displays the contents of the array argument*/ void get_array(int a[4][2])

{

int i, j;

printf("\nHere is the same array as accessed from C:\n\n"); for (i = 0; i < 4; i++)

for (j = 0; j < 2; j++)

printf(“a[%d][%d] = %d\n”, i, j, a[i][j]);

}

Here are the command lines to compile, link, and execute the program, followed by the output from a sample run:

$ cc -Aa -c get_array.c

$ f90 pass_array.f90 get_array.o

$ a.out

Here is how Fortran stores the array:

my_array(1,1) = 1 my_array(2,1) = 2 my_array(1,2) = 3 my_array(2,2) = 4 my_array(1,3) = 5 my_array(2,3) = 6 my_array(1,4) = 7 my_array(2,4) = 8

Here is the same array as accessed from C:

a[0][0] = 1 a[0][1] = 2 a[1][0] = 3 a[1][1] = 4 a[2][0] = 5 a[2][1] = 6 a[3][0] = 7 a[3][1] = 8

Arrays 117