-asume bscc is broken (ifort ver 15.0.2)

[Marc__Jan]

Following program: 

      program bsccbroken                                                                                                                                                         

      write(*,*) '\"ABCDEF\"'
      write(*,*) '\"ABCDEF\"\0'
      write(*,*) '\"#\"'
      write(*,*) '\"#\"\0'

      end program bsccbroken

When compiled with ifort version 15.0.2:

ifort -assume bscc -warn all -g -o bscc bscc.f

Produces following output:

[bma@localhost f]$ ./bscc
 "ABCDEF"
 "ABCDEF
 "#"
 "#
 

Please notice that closing quote is not included when \0 is appended to the end of the string. I work with large legacy code base where those closing zero bytes (\0) are very often included to ensure interoperability with C APIs.

While using IBM fortran xlf90 produces expected result:

$ xlf90 -o bscc bscc.f
** bsccbroken   === End of Compilation 1 ===
1501-510  Compilation successful for file bscc.f.
$ ./bscc
 "ABCDEF"
 "ABCDEF"
 "#"
 "#"
 

Is it well known problem with -assume bscc option? Is there a patch for this? Is this behavior different in newer versions of Composer Studio?

Thanks in advance for any information.

[Steve_Lionel]

The problem here is that Intel Fortran doesn't recognize \" as a valid escape sequence (reference). The manual says:

If a string contains an escape sequence that isn't in this table, the backslash is ignored.

I admit it is a bit weird that it throws away the \0 in this case - that may be a bug in itself. If you don't have any unrecognized sequences, then \0 is processed properly.

I was able to reproduce this behavior in 19.0.5.

[Marc__Jan]

Thank you for your response. For the time being I fixed the application code by removing redundant backslash before ".