s2c(3f) - [M_strings:ARRAY] convert character variable to array of
characters with last element set to null
(LICENSE:PD)
function s2c(string)
character(len=*),intent=(in) :: string
character(len=1),allocatable :: s2c(:)
Given a character variable convert it to an array of single-character
character variables with the last element set to a null character.
This is generally used to pass character variables to C procedures.
Sample Program:
program demo_s2c
use M_strings, only : s2c
implicit none
character(len=*),parameter :: string="single string"
character(len=3),allocatable :: array(:)
write(*,*)'INPUT STRING ',trim(string)
! put one character into each 3-character element of array
array=s2c(string)
! write array with ASCII Decimal Equivalent below it except show
! unprintable characters like NULL as "XXX"
write(*,'(1x,*("[",a3,"]":))')&
& merge('XXX',array,iachar(array(:)(1:1)) < 32)
write(*,'(1x,*("[",i3,"]":))')&
& iachar(array(:)(1:1))
end program demo_s2c
Expected output:
INPUT STRING single string
[s ][i ][n ][g ][l ][e ][ ][s ][t ][r ][i ][n ][g ][XXX]
[115][105][110][103][108][101][ 32][115][116][114][105][110][103][ 0]
John S. Urban
Public Domain
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| character(len=*), | intent(in) | :: | string |
pure function s2c(string) RESULT (array)
use,intrinsic :: ISO_C_BINDING, only : C_CHAR
! ident_27="@(#) M_strings s2c(3f) copy string(1 Clen(string)) to char array with null terminator"
character(len=*),intent(in) :: string
! This is changing, but currently the most portable way to pass a CHARACTER variable to C is to convert it to an array of
! character variables with length one and add a null character to the end of the array. The s2c(3f) function helps do this.
character(kind=C_CHAR,len=1) :: array(len_trim(string)+1)
integer :: i
do i = 1,size(array)-1
array(i) = string(i:i)
enddo
array(size(array):)=achar(0)
end function s2c