RTL Functions

As the frontend of the Fortran language, Flang contains a list of RTL (runtime library) function routines. All functions in the RTL function list are built-in functions. BiSheng prefixes these functions with bs_. When writing code in the Fortran language, the user should not call functions with the same names to prevent function redefinition.

Interface Example

FtnRteRtn ftnRtlRtns[] = { 
{"f90io_aux_init", "", false, ""}, 
    {"f90io_backspace", "", false, ""}, 
    {"f90io_begin", "", false, ""}, 
......

Usage Example

These runtime functions are named with a special prefix bs_f90. The following is an incorrect usage example:

INTEGER FUNCTION bs_f90io_sc_i_ldw(i, j) 
  IMPLICIT NONE 
  INTEGER, INTENT(in):: i 
  INTEGER, INTENT(INOUT):: j 
  print *, i,j 
  j = j + 1 
END FUNCTION bs_f90io_sc_i_ldw

In this example, the Fortran statement print is used for the preceding RTL function bs_f90io_sc_cf_ldw. As a result, the following errors occur during compilation:

F90-W-0155-bs_f90io_sc_i_ldw - PURE subprograms may not contain external I/O statements (f90io_sc_i_ldw.f90: 5) 
  0 inform,   1 warnings,   0 severes, 0 fatal for bs_f90io_sc_i_ldw 
F90-S-0000-Internal compiler error. gen_funcret: illegal dtype, sym       0  (f90io_sc_i_ldw.f90: 7) 
F90-S-0000-Internal compiler error. get_llvm_name: bad stype for       0  (f90io_sc_i_ldw.f90: 7) 
...... 
F90-S-0000-Internal compiler error. get_llvm_name: bad stype for       0  (f90io_sc_i_ldw.f90: 7) 
F90-F-0000-Internal compiler error. make_lltype_from_sptr(), no incoming arguments       0  (f90io_sc_i_ldw.f90: 7)

Parent topic: Intrinsic Procedures