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Subject: Re: conflicting types for bzero (gcc303)
From: Tim Van Holder <tim DOT van DOT holder AT pandora DOT be>
To: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
Cc: djgpp-workers AT delorie DOT com, ST001906 AT HRZ1 DOT HRZ DOT TU-Darmstadt DOT De
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Date: 07 Feb 2002 11:45:45 +0100
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On Thu, 2002-02-07 at 10:49, Eli Zaretskii wrote:
> 
> On 7 Feb 2002, Tim Van Holder wrote:
> 
> > The point is that gcc only complains if you force it to use our own
> > headers by explicitly listing -I$DJDIR/include on the command line.
> 
> No, it will complain if you compile a program that includes string.h and 
> calls bzero/bcopy, even if you don't use any -I switches.

Really?

$ cat foo.c
#include <string.h>

void foo() { bzero (NULL, 0); }
$ i586-pc-msdosdjgpp-gcc -v                         
Reading specs from /opt/gcc3/lib/gcc-lib/i586-pc-msdosdjgpp/3.0.1/specs
Configured with: ../gcc/configure --target=i586-pc-msdosdjgpp
--prefix=/opt/gcc3
Thread model: single
gcc version 3.0.1 20010618 (prerelease)

$i586-pc-msdosdjgpp-gcc -S foo.c -o /dev/null -Wall -v
Reading specs from /opt/gcc3/lib/gcc-lib/i586-pc-msdosdjgpp/3.0.1/specs
Configured with: ../gcc/configure --target=i586-pc-msdosdjgpp
--prefix=/opt/gcc3
Thread model: single
gcc version 3.0.1 20010618 (prerelease)
 /opt/gcc3/lib/gcc-lib/i586-pc-msdosdjgpp/3.0.1/cc1 -lang-c -v
-D__GNUC__=3 -D__GNUC_MINOR__=0 -D__GNUC_PATCHLEVEL__=1 -D__MSDOS__
-D__GO32__ -D__MSDOS__ -D__GO32__ -Asystem=msdos -D__NO_INLINE__
-D__STDC_HOSTED__=1 -Wall -remap -Acpu=i386 -Amachine=i386 -Di386
-D__i386 -D__i386__ -D__tune_i586__ -D__tune_pentium__ -DMSDOS -DGO32
-imacros
/opt/gcc3/lib/gcc-lib/i586-pc-msdosdjgpp/3.0.1/../../../../i586-pc-msdosdjgpp/lib/../include/sys/version.h foo.c -quiet -dumpbase foo.c -Wall -version -o /dev/null
GNU CPP version 3.0.1 20010618 (prerelease) (cpplib) (80386, BSD syntax)
GNU C version 3.0.1 20010618 (prerelease) (i586-pc-msdosdjgpp)
	compiled by GNU C version 3.0 20010514 (prerelease).
#include "..." search starts here:
#include <...> search starts here:
 /opt/gcc3/lib/gcc-lib/i586-pc-msdosdjgpp/3.0.1/include
 /opt/gcc3/i586-pc-msdosdjgpp/sys-include
 /opt/gcc3/i586-pc-msdosdjgpp/include
End of search list.

$i586-pc-msdosdjgpp-gcc -S foo.c -o /dev/null -Wall -I
/opt/gcc3/i586-pc-msdosdjgpp/sys-include -v
Reading specs from /opt/gcc3/lib/gcc-lib/i586-pc-msdosdjgpp/3.0.1/specs
Configured with: ../gcc/configure --target=i586-pc-msdosdjgpp
--prefix=/opt/gcc3
Thread model: single
gcc version 3.0.1 20010618 (prerelease)
 /opt/gcc3/lib/gcc-lib/i586-pc-msdosdjgpp/3.0.1/cc1 -lang-c -v -I
/opt/gcc3/i586-pc-msdosdjgpp/sys-include -D__GNUC__=3 -D__GNUC_MINOR__=0
-D__GNUC_PATCHLEVEL__=1 -D__MSDOS__ -D__GO32__ -D__MSDOS__ -D__GO32__
-Asystem=msdos -D__NO_INLINE__ -D__STDC_HOSTED__=1 -Wall -remap
-Acpu=i386 -Amachine=i386 -Di386 -D__i386 -D__i386__ -D__tune_i586__
-D__tune_pentium__ -DMSDOS -DGO32 -imacros
/opt/gcc3/lib/gcc-lib/i586-pc-msdosdjgpp/3.0.1/../../../../i586-pc-msdosdjgpp/lib/../include/sys/version.h foo.c -quiet -dumpbase foo.c -Wall -version -o /dev/null
GNU CPP version 3.0.1 20010618 (prerelease) (cpplib) (80386, BSD syntax)
GNU C version 3.0.1 20010618 (prerelease) (i586-pc-msdosdjgpp)
	compiled by GNU C version 3.0 20010514 (prerelease).
ignoring duplicate directory "/opt/gcc3/i586-pc-msdosdjgpp/sys-include"
#include "..." search starts here:
#include <...> search starts here:
 /opt/gcc3/i586-pc-msdosdjgpp/sys-include
 /opt/gcc3/lib/gcc-lib/i586-pc-msdosdjgpp/3.0.1/include
 /opt/gcc3/i586-pc-msdosdjgpp/include
End of search list.
In file included from foo.c:1:
/opt/gcc3/i586-pc-msdosdjgpp/sys-include/string.h:53: warning:
conflicting types for built-in function `bzero'


This is with gcc 3.0.1 on Linux, but I see the same behaviour with
gcc 3.0.[23] on WinXP.

> > If you don't do so, I assume it uses its own private version.
> 
> We cannot tell users not to use string.h in their programs.  Having 
> prototypes visible to the compiler is a good programming practice; -Wall 
> flags functions without prototypes, so if they use -W* switches, they 
> will have a warning one way or the other.
> 
> We should fix this.

I wasn't saying we don't need to fix it in our headers.
I was merely saying that the specific case reported by Juan Manuel could
be solved by editing the Makefile or by using specific options for
configure.