Technical data

Fortran/C Wrapper Interface

character array When using mkf2c to call C from Fortran, the address of the

Fortran character variable is passed. This character array

can be modiﬁed by C. It is not guaranteed to be null

terminated. The length of the Fortran character variable is

treated differently (as discussed in the next section).

pointer The value found on the stack is treated as a pointer and is

passed without alteration. Any array or pointer that is not

of type char, any parameter with multiple levels of

indirection, or any indirect array is assumed to be of type

pointer. If the type of a parameter is speciﬁed but is not one

of the standard C types, mkf2c will pass it as a pointer.

Below is an example of a C speciﬁcation for a function:

test (i,s,c,ptr1,ar1,u,f,d,d1,str1,str2,str3)

short s;

unsigned char c;

int *ptr1;

char *ptr2[];

short ar1[];

sometype u;

float f;

long float d, *d1;

char *str1;

char str2[],str3[30];

{

/* The C function body CAN go here. Nothing

except the opening and closing braces are

necessary */

If this function were passed to mkf2c, the parameters would be transformed

as follows:

• PTR1, PTR2, AR1, D1, and U would be passed as simple pointers.

• mkf2c would complain about not understanding the type SOMETYPE

but, by default, would assume it to be of type POINTER.