変数のsave属性

SAVE属性の解説

http://www7b.biglobe.ne.jp/~fortran/education/fortran90/sec8.html

http://jjoo.sakura.ne.jp/tips/f90/initial_save.html

サンプル

2019-01-29_13-22

/work2/am/TOOLS/CODING_SAMPLE/FORTRAN_SAVE

am@localhost

$ cat fortran_save.f90

program fortran_save

a=100

call sub(a,b)

call sub_save(a,b)

a=0

call sub_save(a,b)

end program fortran_save

subroutine sub(a)

real,intent(in)::a

print *,'IN SUB: a=',a

end subroutine sub

subroutine sub_save(a)

real,intent(in)::a

real,save::b

print *,'IN SUB_SAVE: a=',a

if(a==100)then

b=a

end if

print *,'IN SUB_SAVE: b=',b

end subroutine sub_save

2019-01-29_13-22

/work2/am/TOOLS/CODING_SAMPLE/FORTRAN_SAVE

am@localhost

$ ifort -o fortran_save.exe fortran_save.f90

2019-01-29_13-22

/work2/am/TOOLS/CODING_SAMPLE/FORTRAN_SAVE

am@localhost

$ fortran_save.exe

IN SUB: a= 100.0000

IN SUB_SAVE: a= 100.0000

IN SUB_SAVE: b= 100.0000

IN SUB_SAVE: a= 0.0000000E+00

IN SUB_SAVE: b= 100.0000