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! Program to test COMMON and EQUIVALENCE.
program common
real (kind=8) a(8)
real (kind=8) b(5), c(5)
common /com1/b,c
equivalence (a(1), b(2))
b = 100
c = 200
call common_pass
call common_par (a, b,c)
call global_equiv
call local_equiv
end
! Use common block to pass values
subroutine common_pass
real (kind=8) a(8)
real (kind=8) b(5), c(5)
common /com1/b,c
equivalence (a(1), b(2))
if (any (a .ne. (/100,100,100,100,200,200,200,200/))) call abort
end subroutine
! Common variables as argument
subroutine common_par (a, b, c)
real (kind=8) a(8), b(5), c(5)
if (any (a .ne. (/100,100,100,100,200,200,200,200/))) call abort
if (any (b .ne. (/100,100,100,100,100/))) call abort
if (any (c .ne. (/200,200,200,200,200/))) call abort
end subroutine
! Global equivalence
subroutine global_equiv
real (kind=8) a(8), b(5), c(5), x(8), y(4), z(4)
common /com2/b, c, y, z
equivalence (a(1), b(2))
equivalence (x(4), y(1))
b = 100
c = 200
y = 300
z = 400
if (any (a .ne. (/100,100,100,100,200,200,200,200/))) call abort
if (any (x .ne. (/200,200,200,300,300,300,300,400/))) call abort
end
! Local equivalence
subroutine local_equiv
real (kind=8) a(8), b(10)
equivalence (a(1), b(3))
b(1:5) = 100
b(6:10) = 200
if (any (a .ne. (/100,100,100,200,200,200,200,200/))) call abort
end subroutine
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