Re: preprocessor/6779: -O option causes preprocessing problems

Re: preprocessor/6779: -O option causes preprocessing problems

[neil]

Synopsis: -O option causes preprocessing problems

State-Changed-From-To: open->closed
State-Changed-By: neil
State-Changed-When: Thu May 23 02:50:36 2002
State-Changed-Why:
    This is the same as the frequently reported non-bug.
    
    Glibc defines printf as a macro if optimization is on.
    At the top of your file, put #undef printf to solve this.
    GCC 3.2 allows you to put directives in macro arguments,
    so this Gblic issue disappears, but the changes will
    not be backported to 3.1 .
    
    Why was the message reported by the compiler unclear to
    you?  I'm worried as I don't think I can make it any clearer.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6779

preprocessor/6779: -O option causes preprocessing problems

[avd]

>Number:         6779
>Category:       preprocessor
>Synopsis:       -O option causes preprocessing problems
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu May 23 02:16:01 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     avd@openlinksw.com
>Release:        gcc-3.1
>Organization:
>Environment:
Linux on x86, glibc 2.2.2
>Description:
My problem is akin of one mentioned among "Frequently Reported Bugs" but is slightly different. gcc-3.1 successfully
compiles my code when optimization is turned off but fails
when it is on. It produces the following error messages:

m.c:9:1: directives may not be used inside a macro argument
m.c:8:6: unterminated argument list invoking macro "printf"

Note that my macro does not have arguments at all.
Perhaps printf is also a macro. But if it works without
optimization why it fails with it?
>How-To-Repeat:
Compile the attached program with and without optimization
and compare the results:

gcc -O m.c

gcc m.c
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: