[Bug fortran/97031] New: the content of a comment line breaks compilation

[Bug fortran/97031] New: the content of a comment line breaks compilation

[jean-pierre.flament@univ-lille.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97031

            Bug ID: 97031
           Summary: the content of a comment line breaks compilation
           Product: gcc
           Version: 4.4.7
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jean-pierre.flament@univ-lille.fr
  Target Milestone: ---

Created attachment 49211
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49211&action=edit
contains  fortran pgm, system and compile info and output

I would like to signal to you a compilation problem that I have solved.

the following comment line

!   some text...  DIR/*/)

seems to put the compiler into trouble. (see attachment)

changing the line to 

!   some text... DIR/d2)

solves the problem

The attached file contains 

1) the fortran (self contained)  
    The faulty line is marked ==> FAULTY LINE,
    it is followed by the line ===> LINE OK
2) the system name  (centos 6.10) and kernel
3) the command to compile
4) the output

all these parts are sepaated by ==============  lines

I have also tested gfortran 6.3 (from devtoolset of centos) on the same
computer (As far as I remember the errors are different but the compilation
fails), and gfortran 4.9.3 also on a centos machine: same as 4.4.7).
Sorry I have not access to newer versions of gfortran

[Bug fortran/97031] the content of a comment line breaks compilation

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97031

kargl at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kargl at gcc dot gnu.org

--- Comment #1 from kargl at gcc dot gnu.org ---
(In reply to jean-pierre.flament from comment #0)
> Created attachment 49211 [details]
> contains  fortran pgm, system and compile info and output
> 
> I would like to signal to you a compilation problem that I have solved.
> 
> the following comment line
> 
> !   some text...  DIR/*/)
> 
> seems to put the compiler into trouble. (see attachment)
> 
> changing the line to 
> 
> !   some text... DIR/d2)
> 
> solves the problem
> 
> The attached file contains 
> 
> 1) the fortran (self contained)  
>     The faulty line is marked ==> FAULTY LINE,
>     it is followed by the line ===> LINE OK
> 2) the system name  (centos 6.10) and kernel
> 3) the command to compile
> 4) the output
> 
> all these parts are sepaated by ==============  lines
> 
> I have also tested gfortran 6.3 (from devtoolset of centos) on the same
> computer (As far as I remember the errors are different but the compilation
> fails), and gfortran 4.9.3 also on a centos machine: same as 4.4.7).
> Sorry I have not access to newer versions of gfortran

This should be closed as INVALID.

You are preprocessing your code with cpp in traditional mode,
and therefore the '/*' in your code is the start of a C comment.
This is an user error.  Not a problem with gfortran.

[Bug fortran/97031] the content of a comment line breaks compilation

[jean-pierre.flament@univ-lille.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97031

--- Comment #2 from jean-pierre.flament@univ-lille.fr ---
Thanks, 

However, if I launch "man cpp" or "man gfortran" I can't see anything in
relation with my problem and traditional.

I just noticed that cpp recognizes the extensions .fpp .F and other uppercase
extensions. 
This is why I added -cpp in the gfortran command (otherwise I have a diagnostic
because of #ifdef's

I have renamed my file with the  .fpp extension; with  "-cpp" in the gfortran
submission I get the same errors.

If I compile the file with extension *.f or .fpp without -cpp  

 1) the compilation has no error 
 2) a #ifdef...#endif is recognized even with a .f extension, without -cpp, in
my simple example, (I should check that the directive really is taken into
account !) 
 3) IF I compile my full project in a makefile, the absence of "-cpp" in the
gfortran command induces 
    a "Illegal preprocessor directive" error in all the routines having that 
#ifdef...#endif


----- Mail original -----
De: "kargl at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
À: "jean-pierre flament" <jean-pierre.flament@univ-lille.fr>
Envoyé: Samedi 12 Septembre 2020 12:14:06
Objet: [Bug fortran/97031] the content of a comment line breaks compilation

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97031

kargl at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kargl at gcc dot gnu.org

--- Comment #1 from kargl at gcc dot gnu.org ---
(In reply to jean-pierre.flament from comment #0)
> Created attachment 49211 [details]
> contains  fortran pgm, system and compile info and output
> 
> I would like to signal to you a compilation problem that I have solved.
> 
> the following comment line
> 
> !   some text...  DIR/*/)
> 
> seems to put the compiler into trouble. (see attachment)
> 
> changing the line to 
> 
> !   some text... DIR/d2)
> 
> solves the problem
> 
> The attached file contains 
> 
> 1) the fortran (self contained)  
>     The faulty line is marked ==> FAULTY LINE,
>     it is followed by the line ===> LINE OK
> 2) the system name  (centos 6.10) and kernel
> 3) the command to compile
> 4) the output
> 
> all these parts are sepaated by ==============  lines
> 
> I have also tested gfortran 6.3 (from devtoolset of centos) on the same
> computer (As far as I remember the errors are different but the compilation
> fails), and gfortran 4.9.3 also on a centos machine: same as 4.4.7).
> Sorry I have not access to newer versions of gfortran

This should be closed as INVALID.

You are preprocessing your code with cpp in traditional mode,
and therefore the '/*' in your code is the start of a C comment.
This is an user error.  Not a problem with gfortran.

[Bug fortran/97031] the content of a comment line breaks compilation

[sgk at troutmask dot apl.washington.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97031

--- Comment #3 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Sun, Sep 13, 2020 at 08:02:01AM +0000, jean-pierre.flament@univ-lille.fr
wrote:
> 
> I just noticed that cpp recognizes the extensions .fpp .F and other uppercase
> extensions. 
> This is why I added -cpp in the gfortran command (otherwise I have a diagnostic
> because of #ifdef's
> 
> I have renamed my file with the  .fpp extension; with  "-cpp" in the gfortran
> submission I get the same errors.
> 
> If I compile the file with extension *.f or .fpp without -cpp  
> 
>  1) the compilation has no error 
>  2) a #ifdef...#endif is recognized even with a .f extension, without -cpp, in
> my simple example, (I should check that the directive really is taken into
> account !) 
>  3) IF I compile my full project in a makefile, the absence of "-cpp" in the
> gfortran command induces 
>     a "Illegal preprocessor directive" error in all the routines having that 
> #ifdef...#endif
> 

I don't quite follow you.  But, it come down to gfortran uses
the C pre-processor when asked to pre-process a file.  If you 
have a C language construct such as '/*' in your Fortran code 
it will cause problems.

[Bug fortran/97031] the content of a comment line breaks compilation

[jean-pierre.flament@univ-lille.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97031

--- Comment #4 from jean-pierre.flament@univ-lille.fr ---
see below:

----- Mail original -----
De: "kargl at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
À: "jean-pierre flament" <jean-pierre.flament@univ-lille.fr>
Envoyé: Dimanche 13 Septembre 2020 11:55:28
Objet: [Bug fortran/97031] the content of a comment line breaks compilation

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97031

--- Comment #3 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Sun, Sep 13, 2020 at 08:02:01AM +0000, jean-pierre.flament@univ-lille.fr
wrote:
> 
> I just noticed that cpp recognizes the extensions .fpp .F and other uppercase
> extensions. 
> This is why I added -cpp in the gfortran command (otherwise I have a diagnostic
> because of #ifdef's
> 
> I have renamed my file with the  .fpp extension; with  "-cpp" in the gfortran
> submission I get the same errors.
> 
> If I compile the file with extension *.f or .fpp without -cpp  
> 
>  1) the compilation has no error 
>  2) a #ifdef...#endif is recognized even with a .f extension, without -cpp, in
> my simple example, (I should check that the directive really is taken into
> account !) 
>  3) IF I compile my full project in a makefile, the absence of "-cpp" in the
> gfortran command induces 
>     a "Illegal preprocessor directive" error in all the routines having that 
> #ifdef...#endif
> 

I don't quite follow you.  But, it come down to gfortran uses
the C pre-processor when asked to pre-process a file.  If you 
have a C language construct such as '/*' in your Fortran code 
it will cause problems.

====> In my remarks just above  2) and 3) I just wanted to point that,
apprently, in addtion, gfortran+cpp seem to have a different behaviour when
called in a makefile or in a simple command line. I can check that more.

===>  as regards the intial point: do you find it normal that, processing a
fortran file (and I imagine that CPP knows that point since it was launched 
within the gfortran command) CPP does not consider fortran comment lines as
such, and ignores their content.
    In addition I noticed that there is a '*/' construct farther in the file in
an other commented line (line = "... */ ...", and that thus all the stuff
inbetween was ignored, suppresing all the declarations  (character and others)
ans some other statements; this explains the diagnostics of the compiler.
     another questions raises:  the '*/' was within " ", i.e. a character
string... a legal fortran statement.
     before commenting this line I had an other message reporting an end for
file before the end of a comment (I don't remember exactly
     the formulation). That's why I  finally decided to create the test file
that you have, commenting all the lines with call's and the famous  line =
"...." . I know understand what happened. 

  but once again: cpp does not seem  to understand the syntax of fortran ! 
this is very annoying !

[Bug fortran/97031] the content of a comment line breaks compilation

[jean-pierre.flament@univ-lille.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97031

--- Comment #5 from jean-pierre.flament@univ-lille.fr ---
I am sorry to bother you once again, for the last time. I have now understood
all things that happened while compiling the very complicated (!) program
below. 

========================
program tstmak
   implicit none
!     a comment with /*
   integer :: i
!
#ifdef _MYDEBUG_
   print *,' debug printing'
#endif
   i = 25
   print *,'normal printing: i=',i
end program tstmak
========================================

I compiled this fortran with and without -cpp, and always with -D_MYDEBUG_ in a
command like that one

gfortran -v -ffree-form -Wall -msse2 -g -fbounds-check -fbacktrace  -D_MYDEBUG_
 -cpp tstmak1.f -o v1

1) if -cpp is PRESENT 
   a) the '/*' in the comment line causes a great problem (in that case an "end
of file") and no executable is produced 
   b) if I change the '/*' to anything else, no message, the executable is
produced, and prints what is expected
2) if -cpp is ABSENT
   a) the '/*' in the comment line has no catastrophic effect, but a WARNING
appears 
      "Warning: tstmak.f:6: Illegal preprocessor directive"
      however the executable is produced, and prints what is expected

It is because of this warning (and not an error) that I always put "-cpp" in my
makefiles !

===> conclusion:  gfortran "tolerates" and understands "#" type directives. 
     This is in opposition to other compilers, which also caused my trouble

Sorry for the  disturbance

JP Flament

----- Mail original -----
De: "kargl at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
À: "jean-pierre flament" <jean-pierre.flament@univ-lille.fr>
Envoyé: Dimanche 13 Septembre 2020 11:55:28
Objet: [Bug fortran/97031] the content of a comment line breaks compilation

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97031

--- Comment #3 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Sun, Sep 13, 2020 at 08:02:01AM +0000, jean-pierre.flament@univ-lille.fr
wrote:
> 
> I just noticed that cpp recognizes the extensions .fpp .F and other uppercase
> extensions. 
> This is why I added -cpp in the gfortran command (otherwise I have a diagnostic
> because of #ifdef's
> 
> I have renamed my file with the  .fpp extension; with  "-cpp" in the gfortran
> submission I get the same errors.
> 
> If I compile the file with extension *.f or .fpp without -cpp  
> 
>  1) the compilation has no error 
>  2) a #ifdef...#endif is recognized even with a .f extension, without -cpp, in
> my simple example, (I should check that the directive really is taken into
> account !) 
>  3) IF I compile my full project in a makefile, the absence of "-cpp" in the
> gfortran command induces 
>     a "Illegal preprocessor directive" error in all the routines having that 
> #ifdef...#endif
> 

I don't quite follow you.  But, it come down to gfortran uses
the C pre-processor when asked to pre-process a file.  If you 
have a C language construct such as '/*' in your Fortran code 
it will cause problems.

[Bug fortran/97031] the content of a comment line breaks compilation

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97031

Dominique d'Humieres <dominiq at lps dot ens.fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2020-10-05
             Status|UNCONFIRMED                 |WAITING
     Ever confirmed|0                           |1

--- Comment #6 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
> This should be closed as INVALID.

I agree!

[Bug fortran/97031] the content of a comment line breaks compilation

[tkoenig at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97031

Thomas Koenig <tkoenig at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
                 CC|                            |tkoenig at gcc dot gnu.org
         Resolution|---                         |INVALID

--- Comment #7 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
I think the documentation for this is adequate:

1.3 Preprocessing and conditional compilation
=============================================

Many Fortran compilers including GNU Fortran allow passing the source
code through a C preprocessor (CPP; sometimes also called the Fortran
preprocessor, FPP) to allow for conditional compilation.  In the case of
GNU Fortran, this is the GNU C Preprocessor in the traditional mode.

If the C preprocessor is used, then C preprocessor rules apply.

Closing.