# Using the same procedure name in Fortran as interfaced C function
**URL:** https://fortran-lang.discourse.group/t/using-the-same-procedure-name-in-fortran-as-interfaced-c-function/5481
**Category:** Help
**Created:** [April 2, 2023, 1:24pm UTC](https://fortran-lang.discourse.group/t/using-the-same-procedure-name-in-fortran-as-interfaced-c-function/5481 "2023-04-02T13:24:34Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@msz59](https://fortran-lang.discourse.group/u/msz59)
#### Post date: [April 2, 2023, 1:24pm UTC](https://fortran-lang.discourse.group/t/using-the-same-procedure-name-in-fortran-as-interfaced-c-function/5481/1 "2023-04-02T13:24:34Z")
This is my first attempt to use modern Fortran to C interfacing. The last time I did something similar was (many years ago) by manually adding underscores to F77 procedure names in wrappers written in C.
My code (just a beginning of a long way) to use a C library from Fortran is:
```fortran
module phot_db
use, intrinsic :: iso_c_binding
contains
integer function opendb(fld, flt) result(res)
character(*), intent(in) :: fld, flt
interface
function opendb_w(fld,flt) bind(c,name="opendb")
import :: c_int, c_char
integer(c_int) :: opendb_w
character(c_char),dimension(*) :: fld, flt
end function opendb_w
end interface
res = opendb_w(trim(fld)//c_null_char, trim(flt)//c_null_char)
end function opendb
end module phot_db
```
As you can see, I tried to give Fortran wrapper the very same name as that of the corresponding C function, using `name` clause in `bind` attribute and giving the interface entry slightly modified name (`opendb_w`) to avoid a recursion loop.
And it works, at least in gfortran. My question is whether this is _legal_ and guaranteed to work in any processor.
Another question is whether one should provide explicit conversion between C-interoperable and standard Fortran types, e.g. `c_int` and `integer`. Surely I would like to avoid using `c_*` types in Fortran programs, outside the interface module.
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### Author:  [@FortranFan](https://fortran-lang.discourse.group/u/FortranFan)
#### Post date: [April 2, 2023, 1:56pm UTC](https://fortran-lang.discourse.group/t/using-the-same-procedure-name-in-fortran-as-interfaced-c-function/5481/2 "2023-04-02T13:56:19Z")
> [@msz59](#):
>
> … I tried to give Fortran wrapper the very same name as that of the corresponding C function .
That conforms and any **conforming** processor shall process the instructions.
Re: “Another question is whether one should provide explicit conversion between C-interoperable and standard Fortran types,” you knew the answer to this second question already when you mentioned “in any processor” in your first question! You know the default integer in any processor may or may not be the same kind as `c_int`, so you can proceed accordingly.
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### Author:  [@msz59](https://fortran-lang.discourse.group/u/msz59)
#### Post date: [April 2, 2023, 2:41pm UTC](https://fortran-lang.discourse.group/t/using-the-same-procedure-name-in-fortran-as-interfaced-c-function/5481/3 "2023-04-02T14:41:59Z")
Thanks @FortranFan for reassuring response.
I had doubts because my (maybe oversimplified) guess was that the only way to make the linker work fine on such a mixed program would be to internally call same-named procedures by slightly different name in Fortran and C. As one can easily see converting F90 code to assembly, both gfortran and ifort do indeed call the (Fortran) function `opendb` as (assembly) `call opendb_` (as it used to be 30 years ago), contrary to the C compiler which does not add anything to the function name. Still, I was not sure how Fortran Standard can assure it is _universal_.