Intel® Fortran Compiler 17.0 Developer Guide and Reference
The commonly used types are included in the following table. The following applies:
Integer types in Fortran are always signed. In C, integer types may be specified as signed or unsigned, but are signed by default.
The values of C_LONG, C_SIZE_T, C_LONG_DOUBLE, and C_LONG_DOUBLE_COMPLEX are different on different platforms.
Named constant from ISO_C_BINDING (kind type parameter if value is positive) |
C type |
Equivalent Fortran type |
|---|---|---|
C_SHORT C_INT C_LONG C_LONG_LONG |
short int int long int long long int |
INTEGER(KIND=2) INTEGER(KIND=4) INTEGER (KIND=4 or 8) INTEGER(KIND=8) |
C_SIGNED_CHAR |
signed char unsigned char |
INTEGER(KIND=1) |
C_SIZE_T |
size_t |
INTEGER(KIND=4 or 8) |
C_INT8_T C_INT16_T C_INT32_T C_INT64_T |
int8_t int16_t int32_t int64_t |
INTEGER(KIND=1) INTEGER(KIND=2) INTEGER(KIND=4) INTEGER(KIND=8) |
C_FLOAT C_DOUBLE C_LONG_DOUBLE |
float double long double |
REAL(KIND=4) REAL(KIND=8) REAL(KIND=8 or 16) |
C_FLOAT_COMPLEX C_DOUBLE_COMPLEX C_LONG_DOUBLE_COMPLEX |
float _Complex double _Complex long double _Complex |
COMPLEX(KIND=4) COMPLEX(KIND=8) COMPLEX(KIND=8 or 16) |
C_BOOL |
_Bool |
LOGICAL(KIND=1) |
C_CHAR |
char |
CHARACTER(LEN=1) |
While there are named constants for all possible C types, every type is not necessarily supported on every processor. Lack of support is indicated by a negative value for the constant in the module.
For a character type to be interoperable, you must either omit the length type parameter or specify it using an initialization expression whose value is one.