Technical data

Fortran/Pascal Interface

Invocation

If you have alternate return labels, you can invoke a Fortran subprogram as

if it were an integer-valued function whose value speciﬁes which alternate

return to use. Alternate return arguments (statement labels) are not passed

to the function but cause an indexed branch in the calling subprogram. If the

subprogram is not a function and has no entry points with alternate return

arguments, the returned value is undeﬁned.

The Fortran statement

call nret (*1,*2,*3)

is treated exactly as if it were the computed goto

goto (1,2,3), nret()

A Pascal function that calls a Fortran subroutine can usually ignore the

return value. Table 3-5 shows equivalent function declarations in Pascal and

Fortran.

Fortran has a built-in data type COMPLEX that does not exist in Pascal.

Therefore, there is no compatible way of returning these values from Pascal.

A character-valued Fortran function is equivalent to a Pascal language

routine with two initial extra arguments: a data address and a length.

Table 3-5 Function Declarations

Pascal Fortran

function dfort_(): double;

function rfort_(): real;

function ifort_(): integer;

double precision function dfort()

real function rfort()

integer function ifort()