Numeric Data Types

Visual Studio 6.0

Normally, passing numeric data does not present a problem. The most important thing to keep in mind when passing numeric types is that in Win32, the C int type is 4 bytes, not 2 bytes, and therefore is equivalent to the Fortran INTEGER*4 type. The COMPLEX type is a special case and is discussed in a later section. The following table summarizes equivalent numeric data types for Fortran, MASM, and C/C++.

Equivalent Fortran, MASM, and C/C++ Numeric Data Types

Fortran MASM C/C++
CHARACTER*1 BYTE unsigned char
INTEGER*1 SBYTE char
(none) WORD unsigned short
INTEGER*2 SWORD short
(none) DWORD unsigned long, unsigned int
INTEGER, INTEGER*4 SDWORD long, int
REAL, REAL*4 REAL4 float
DOUBLE PRECISION, REAL*8 REAL8 double

If a C program passes an unsigned data type to a Fortran routine, the routine can accept the argument as the equivalent signed data type, but you should be careful that the range of the signed type is not exceeded.

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