20.2. Data Types

Generally, the Fortran 2003 type that is equivalent to the C type is what one would expect. Primitive types map to the iso_c_binding type equivalent. SUNDIALS classes map to a Fortran derived type. However, the handling of pointer types is not always clear as they can depend on the parameter direction. Table 20.2 presents a summary of the type equivalencies with the parameter direction in mind.

Warning

Currently, the Fortran 2003 interfaces are only compatible with SUNDIALS builds where the sunrealtype is double-precision.

Changed in version 7.1.0: The Fortran interfaces can now be built with 32-bit sunindextype in addition to 64-bit sunindextype.

Table 20.2 C/Fortran-2003 Equivalent Types. `T` represents any type.
C Type	Parameter Direction	Fortran 2003 type
`SUNComm`	in, inout, out, return	`integer(c_int)`
`SUNErrCode`	in, inout, out, return	`integer(c_int)`
`double`	in, inout, out, return	`real(c_double)`
`int`	in, inout, out, return	`integer(c_int)`
`long`	in, inout, out, return	`integer(c_long)`
`sunbooleantype`	in, inout, out, return	`integer(c_int)`
`sunrealtype`	in, inout, out, return	`real(c_double)`
`sunindextype`	in, inout, out, return	`integer(c_long)`
`double*`	in, inout, out	`real(c_double), dimension(*)`
`double*`	return	`real(c_double), pointer, dimension(:)`
`int*`	in, inout, out	`real(c_int), dimension(*)`
`int*`	return	`real(c_int), pointer, dimension(:)`
`long*`	in, inout, out	`real(c_long), dimension(*)`
`long*`	return	`real(c_long), pointer, dimension(:)`
`sunrealtype*`	in, inout, out	`real(c_double), dimension(*)`
`sunrealtype*`	return	`real(c_double), pointer, dimension(:)`
`sunindextype*`	in, inout, out	`real(c_long), dimension(*)`
`sunindextype*`	return	`real(c_long), pointer, dimension(:)`
`sunrealtype[]`	in, inout, out	`real(c_double), dimension(*)`
`sunindextype[]`	in, inout, out	`integer(c_long), dimension(*)`
`SUNAdaptController`	in, inout, out	`type(SUNAdaptController)`
`SUNAdaptController`	return	`type(SUNAdaptController), pointer`
`SUNAdjointCheckpointScheme`	in, inout, out, return	`type(c_ptr)`
`SUNAdjointStepper`	in, inout, out, return	`type(c_ptr)`
`SUNDomEigEstimator`	in, inout, out	`type(SUNDomEigEstimator)`
`SUNDomEigEstimator`	return	`type(SUNDomEigEstimator), pointer`
`SUNMatrix`	in, inout, out	`type(SUNMatrix)`
`SUNMatrix`	return	`type(SUNMatrix), pointer`
`SUNLinearSolver`	in, inout, out	`type(SUNLinearSolver)`
`SUNLinearSolver`	return	`type(SUNLinearSolver), pointer`
`SUNNonlinearSolver`	in, inout, out	`type(SUNNonlinearSolver)`
`SUNNonlinearSolver`	return	`type(SUNNonlinearSolver), pointer`
`N_Vector`	in, inout, out	`type(N_Vector)`
`N_Vector`	return	`type(N_Vector), pointer`
`FILE*`	in, inout, out, return	`type(c_ptr)`
`void*`	in, inout, out, return	`type(c_ptr)`
`T**`	in, inout, out, return	`type(c_ptr)`
`T***`	in, inout, out, return	`type(c_ptr)`
`T****`	in, inout, out, return	`type(c_ptr)`