BTEST

Elemental Intrinsic Function (Generic): Tests a bit of an integer argument.

result = BTEST (i,pos)

(Input) Must be of type integer or of type logical (which is treated as an integer).

pos

(Input) Must be of type integer. It must not be negative and it must be less than BIT_SIZE(i).

The rightmost (least significant) bit of i is in position 0.

Results

The result type is default logical.

The result is true if bit pos of i has the value 1. The result is false if pos has the value zero. For more information, see Bit Functions.

For information on the model for the interpretation of an integer value as a sequence of bits, see Model for Bit Data.

The setting of compiler options specifying integer size can affect this function.

BTEST (9, 3) has the value true.

If A has the value

  [ 1  2 ]
  [ 3  4 ],

the value of BTEST (A, 2) is

  [ false  false ]
  [ false   true ]

and the value of BTEST (2, A) is

  [ true   false ]
  [ false  false ].

The following shows more examples:

Function reference	Value of `i`	Result
BTEST ( `i`,2)	00011100 01111000	.FALSE.
BTEST ( `i`,3)	00011100 01111000	.TRUE.

The following shows another example:

INTEGER(1) i(2)
LOGICAL result(2)
i(1) = 2#10101010
i(2) = 2#01010101
result = BTEST(i, (/3,2/))   ! returns (.TRUE.,.TRUE.)
write(*,*) result