---

8.51 BTEST — Bit test function ¶

Synopsis:

RESULT = BTEST(I, POS)

Description:

BTEST(I,POS) returns logical .TRUE. if the bit at POS in I is set. The counting of the bits starts at 0.

Class:

Elemental function

Arguments:

I	The type shall be INTEGER or UNSIGNED.
POS	The type shall be INTEGER.

Return value:

The return value is of type LOGICAL

Example:

program test_btest
    integer :: i = 32768 + 1024 + 64
    integer :: pos
    logical :: bool
    do pos=0,16
        bool = btest(i, pos) 
        print *, pos, bool
    end do
end program test_btest

Specific names:

Name	Argument	Return type	Standard
BTEST(I,POS)	INTEGER I,POS	LOGICAL	Fortran 95 and later
BBTEST(I,POS)	INTEGER(1) I,POS	LOGICAL(1)	GNU extension
BITEST(I,POS)	INTEGER(2) I,POS	LOGICAL(2)	GNU extension
BJTEST(I,POS)	INTEGER(4) I,POS	LOGICAL(4)	GNU extension
BKTEST(I,POS)	INTEGER(8) I,POS	LOGICAL(8)	GNU extension

Standard:

Fortran 90 and later, has overloads that are GNU extensions; extension for UNSIGNED (see Unsigned integers)