What happens with this Allocate?

[dajum81]

SUBROUTINE STRCPY(STR1,STR2,N)

C

C @(#)strcpy.F 3.2 11/21/89

C

C Purpose:

C COPIES UP TO N CHAR OF STR2 TO STR1

C

C Argument List Definitions:

C STR1   - String to copy into

C STR2   - String to copy from

C N      - Max char to copy

C

C---------END OF DESCRIPTION -------

C

USE CSTR_MOD 

CHARACTER*(*) STR1,STR2

CHARACTER(len=:), allocatable :: dest

include 'cdefsu.inc'

I = MIN(N,LEN(STR2))

IF(use_cstr) THEN

allocate(character(len=I) :: dest)

call cstrcpy(dest, STR2, I)

STR1 = dest

RETURN

END IF

C

STR1 = ' '

STR1(1:I) = STR2(1:I)

RETURN

END

So what happens with this subroutine local variable being allocated every call, but never deallocated?  It doesn't crash with a message saying it was already allocated on the subsequent calls.  It seems to work fine most of the time.  But I have a case where I get a crash, but if I add a deallocate it doesn't crash.  So I suspect memory corruption, but I'm not sure how the compiler handles this situation because it is just a subroutine local variable.

Thanks,

Dave

[Steve_Lionel]

Local variables with the ALLOCATABLE attribute but not SAVE get automatically deallocated when the procedure returns.

[dajum81]

Thanks Steve, any thoughts on why adding a deallocate statement causes my code to not crash?  

[dajum81]

I think I can answer my own question.  I think the automatic deallocation checks the heap which was corrupted by code in another routine, but not checked there.  

[Steve_Lionel]

Glad to hear you got it sorted out.