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Manual Reference Pages  - ibset (3fortran)

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NAME

IBSET(3) - [BIT:SET] Set a bit to one in an integer value

SYNOPSIS

result = ibset(i, pos)

         elemental integer(kind=KIND) function ibset(i,pos)

          integer(kind=KIND),intent(in) :: i
          integer(kind=**),intent(in) :: pos

CHARACTERISTICS

o	a kind designated as ** may be any supported kind for the type
o	The return value is of the same kind as I. Otherwise, any integer kinds are allowed.

DESCRIPTION

IBSET(3) returns the value of I with the bit at position POS set to one.

OPTIONS

o	I : The initial value to be modified
o	POS : The position of the bit to change in the input value. A value of zero refers to the right-most bit. The value of POS must be nonnegative and less than (BIT_SIZE(I)).

RESULT

The returned value has the same bit sequence as I except the designated bit is unconditionally set to 1.

EXAMPLES

Sample program:

    program demo_ibset
    use,intrinsic :: iso_fortran_env,  only : int8, int16, int32, int64
    implicit none
    integer(kind=int16) :: i
      ! basic usage
       print *,ibset (12, 1), ’ibset(12,1) has the value 14’

       ! it is easier to see using binary representation
       i=int(b’0000000000000110’,kind=int16)
       write(*,’(b16.16,1x,i0,1x,i0)’) ibset(i,12), ibset(i,12), i

      ! elemental
       print *,’an array of initial values may be given as well’
       print *,ibset(i=[0,4096], pos=2)
       print *
       print *,’a list of positions results in multiple returned values’
       print *,’not multiple bits set in one value, as the routine is  ’
       print *,’a scalar function; calling it elementally essentially  ’
       print *,’calls it multiple times.                               ’
       write(*,’(b16.16)’) ibset(i=0, pos=[1,2,3,4])

       ! both may be arrays if of the same size

    end program demo_ibset

Results:

     >           14 ibset(12,1) has the value 14
     > 0001000000000110 4102 6
     >  an array of initial values may be given as well
     >            4        4100
     >
     >  a list of positions results in multiple returned values
     >  not multiple bits set in one value, as the routine is
     >  a scalar function; calling it elementally essentially
     >  calls it multiple times.
     > 0000000000000010
     > 0000000000000100
     > 0000000000001000
     > 0000000000010000

STANDARD

Fortran 95

SEE ALSO

IBCLR(3)

BTEST(3), IAND(3), IBITS(3), IEOR(3), IOR(3), MVBITS(3), NOT(3)

fortran-lang intrinsic descriptions (license: MIT) @urbanjost

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Nemo Release 3.1

ibset (3fortran)

April 28, 2024

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