組み込み関数 TRIM の挙動の確認

main.f90

! gfortran, gcc version 7.4.0
! https://stdlib.fortran-lang.org/sourcefile/stdlib_strings.fypp.html

program test

    use , intrinsic :: iso_fortran_env
    implicit none

    character(len=1) , parameter :: ASCII_HT = achar(int(Z'09'))
    character(len=1) , parameter :: ASCII_LF = achar(int(Z'0A'))
    character(len=1) , parameter :: ASCII_VT = achar(int(Z'0B'))
    character(len=1) , parameter :: ASCII_FF = achar(int(Z'0C'))
    character(len=1) , parameter :: ASCII_CR = achar(int(Z'0D'))
    
    call test_trim('A' // ASCII_HT // 'Z')
    call test_trim('A' // ASCII_LF // 'Z')
    call test_trim('A' // ASCII_VT // 'Z')
    call test_trim('A' // ASCII_FF // 'Z')
    call test_trim('A' // ASCII_CR // 'Z')
    
    contains
    
    subroutine test_trim (string)
    
        ! arguments
        character(len=3) , intent(in) :: string
    
        print * , ''
        print * , string       , len(string)
        print * , trim(string) , len(trim(string))
        print * , '12345678'
        return

    end subroutine test_trim

end program test

output.txt

 A	Z           3
 A	Z           3
 12345678
 
 A
Z           3
 A
Z           3
 12345678
 
 AZ           3
 AZ           3
 12345678
 
 AZ           3
 AZ           3
 12345678
 
 AZ           3
 AZ           3
 12345678