This module contains some supplementary material useful for writing GTK programs in Fortran. The functions are not listed in the gtk-fortran-index.csv file, either because they are not (currenty) extracted by the automatic tools, or because they are just convenient functions added here.

module gtk_sup

Currently it contains:

• GTYPE: Definitions of the integer length and the values for each type.
• GtkTreeIter: Type definition, and its clear procedure.
• GValue: Pseudo type definition, and its clear procedure.
• GtkTextIter: Type definition.
• GError: Type definition.
• Interfaces for string conversions.
• Boolean conversion routines.
• Miscellaneous functions.

The various Gtype definitions from the gtype.h file.

These structures are always allocated in the calling program, rather than being declared as pointers and leaving GTK to allocate them.

• GtkTreeIter, Iterator for TreeView widgets
• GtkTextIter, Iterator for TextView widgets
• GValue, A value container.

GError is a transparent structure that returns error information.

  subroutine clear_gtktreeiter(iter)
    type(gtktreeiter), intent(inout) :: iter

Clear a tree iterator

  subroutine clear_gvalue(gval)
    type(gvalue), intent(inout) :: gval

Clear a GValue

  subroutine c_f_string_copy_alloc(the_ptr, f_string)
    type(c_ptr), intent(in) :: the_ptr
    character(:), intent(out), allocatable :: f_string
    character(kind=c_char), pointer :: f_array(:)
    integer :: i

Create a default character deferred length allocatable copy of the value of a C string. This function should be preferred to c_f_string_copy() when using a Fortran>=2008 compiler. An advantage is that the trim() function will generally not be needed.

  subroutine c_f_string_copy(the_ptr, f_string, status)
    type(c_ptr), intent(in) :: the_ptr
    character(*), intent(out) :: f_string
    integer, intent(out), optional :: status
    character(kind=c_char), pointer :: f_array(:)
    integer :: i

Create a default character fixed length copy of the value of a C string.

If the Fortran string is too short, the C string is truncated.

  subroutine c_f_string_chars(c_string, f_string)
    character(len=1, kind=C_char), intent(in) :: c_string(*)
    character(len=*), intent(out) :: f_string
    integer :: i

Copy a C string, passed as a char-array reference, to a Fortran string. String routine from C_interface_module by Joseph M. Krahn: https://fortranwiki.org/fortran/show/c_interface_module

  subroutine c_f_string_ptr(c_string, f_string)
    type(C_ptr), intent(in) :: c_string
    character(len=*), intent(out) :: f_string
    character(len=1, kind=C_char), dimension(:), pointer :: p_chars
    integer :: i

Copy a C string, passed by pointer, to a Fortran string. If the C pointer is NULL, the Fortran string is blanked. c_string must be NUL terminated, or at least as long as f_string. If c_string is longer, it is truncated. Otherwise, f_string is blank-padded at the end.

  subroutine convert_c_string_scalar(textptr, f_string, status)
    character(kind=c_char), dimension(:), intent(in) :: textptr
    character(len=*), intent(out) :: f_string
    integer(c_int), intent(out), optional :: status

Convert a null-terminated C-string to a Fortran string

Usually called via the convert_c_string generic interface.

  subroutine convert_c_string_array(textptr, f_string, status)
    character(kind=c_char), dimension(:), intent(in) :: textptr
    character(len=*), intent(out), dimension(:), allocatable :: f_string
    integer, intent(out), optional :: status

Convert a null-terminated LF-separated C-string into a Fortran string array

Usually called via the convert_c_string generic interface.

  subroutine convert_c_string_scalar_cptr(ctext, f_string, status)
    type(c_ptr), intent(in) :: ctext
    character(len=*), intent(out) :: f_string
    integer, intent(out), optional :: status

Convert a null-terminated C-string to a Fortran string

Usually called via the convert_c_string generic interface.

  subroutine convert_c_string_array_cptr(ctext, f_string, status)
    type(c_ptr), intent(in) :: ctext
    character(len=*), intent(out), dimension(:), allocatable :: f_string
    integer, intent(out), optional :: status

Convert a null-terminated LF-separated C-string into a Fortran string array

Usually called via the convert_c_string generic interface.

  subroutine convert_f_string_a(f_string, textptr, length)
    character(len=*), intent(in), dimension(:) :: f_string
    character(kind=c_char), dimension(:), intent(out), allocatable :: textptr
    integer(c_int), intent(out), optional :: length

Convert a Fortran string array into a null-terminated, LF_separated C-string

  subroutine convert_f_string_s(f_string, textptr, length)
    character(len=*), intent(in) :: f_string
    character(kind=c_char), dimension(:), intent(out), allocatable :: textptr
    integer(c_int), intent(out), optional :: length

Convert a Fortran string into a null-terminated C-string

  function c_f_logical(cbool)
    logical :: c_f_logical
    integer(c_int), intent(in) :: cbool

Convert a gboolean to a Fortran logical

  function f_c_logical4(flog)
    integer(c_int) :: f_c_logical4
    logical, intent(in) :: flog

Convert a Fortran default logical to a gboolean

Usually accessed via the generic f_c_logical interface

  function f_c_logical1(flog)
    integer(c_int) :: f_c_logical1
    logical(1), intent(in) :: flog

Convert a Fortran 1-byte logical to a gboolean

Usually accessed via the generic f_c_logical interface

  function is_UNIX_OS()
    use g, only: g_get_current_dir

    logical :: is_UNIX_OS
    character(:), allocatable :: path

Returns .true. if the OS is of the UNIX type. On a Windows system, it will return .false. because an absolute path can not begin by a slash.

  function fdate()
    character(29) :: fdate
    character(8)  :: date
    character(10) :: time
    character(5)  :: zone

Returns date, time and timezone in a string without spaces, for example: 2022-05-06T15:58:43.790+02:00