[Qemu-devel] Re: "Enable _FORTIFY_SOURCE=2" result in building failure for qemu-img.c

[Paolo Bonzini <pbonzini@redhat.com>]

On 02/04/2010 08:04 AM, Sheng Yang wrote:
> Got this building failure:
>
> In file included from qemu-img.c:68:
> qemu-img-cmds.h:22:1: error: unterminated argument list invoking macro
> "printf"
> cc1: warnings being treated as errors
> qemu-img.c: In function ‘help’:
> qemu-img.c:95: warning: statement with no effect
> qemu-img.c:71: error: expected ‘;’ before string constant
> qemu-img.c:95: error: expected statement before ‘)’ token
> make: *** [qemu-img.o] Error 1
>
> And git bisect figure out the commit: 84958305, "Enable _FORTIFY_SOURCE=2".
>
> And the code is here:
>
>      printf("qemu-img version " QEMU_VERSION ", Copyright (c) 2004-2008 Fabrice
> Bellard\n"
>             "usage: qemu-img command [command options]\n"
>             "QEMU disk image utility\n"
>             "\n"
>             "Command syntax:\n"
> #define DEF(option, callback, arg_string)        \
>             "  " arg_string "\n"
> #include "qemu-img-cmds.h"
> #undef DEF
> #undef GEN_DOCS
> ....
>
> Seems gcc take "printf" as a marco. I added a "#undef printf" before the line,
> then it works...

It's glibc, not gcc.

I suggest moving the help message into a variable and changing the 
printf to "fputs (help_msg, stdout);".  Would you make a patch?

Paolo