Glibc on target 32 bits with 64-bit time support

Glibc on target 32 bits with 64-bit time support

[Alain GUILLEMOT]

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Hello

I would like to test the transition to 2038 on a 32-bit machine.
For that I would like to compile the glibc in 32 bits with the 64-bit "time_t" options.
But I don't know how to proceed.
In which file I have to add the option "-D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64", or are these options to be passed on the command line?

Currently I change the "configure" adding to  CFLAGS/CXXFLAGS flags, and also exporting CPPFLAGS with same options. But I always have compilation errors.

/tmp/ccb7zYZG.s: Assembler messages:
/tmp/ccb7zYZG.s:641: Error: symbol `__sigtimedwait64' is already defined
make[2]: *** [/tmp/obj/sysd-rules:111: /tmp/obj/signal/sigtimedwait.o] Error 1
make[2]: *** Waiting for unfinished jobs....
In file included from ../sysdeps/generic/hp-timing.h:22,
                 from ../nptl/descr.h:26,
                 from ../sysdeps/arm/nptl/tls.h:39,
                 from ../sysdeps/unix/sysv/linux/arm/tls.h:23,
                 from ../sysdeps/unix/sysv/linux/arm/sysdep.h:28,
                 from ../sysdeps/unix/sysv/linux/internal-signals.h:28,
                 from ../sysdeps/posix/signal.c:22:
../include/time.h:21:1: warning: asm declaration ignored due to conflict with previous rename [-Wpragmas]
   21 | libc_hidden_proto (mktime)
      | ^~~~~~~~~~~~~~~~~
../include/time.h:22:1: warning: asm declaration ignored due to conflict with previous rename [-Wpragmas]
   22 | libc_hidden_proto (timelocal)


Thank's.

Re: Glibc on target 32 bits with 64-bit time support

[Florian Weimer]

* Alain GUILLEMOT:

> In which file I have to add the option "-D_FILE_OFFSET_BITS=64
> -D_TIME_BITS=64", or are these options to be passed on the command
> line?

All ABI variants are automatically built.  You don't have to do anything
while building glibc.  These flags are for building applications with
glibc.

Thanks,
Florian

RE: Glibc on target 32 bits with 64-bit time support

[Alain GUILLEMOT]

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Hi Florian

In « glibc-2.34/configure » file, for "   CFLAGS="-g -O2 -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64"" and CXXFLAGS, and with CPPFLAGS environment variable.

A+


De : Florian Weimer <fweimer@redhat.com>
Envoyé : lundi 15 mai 2023 22:12
À : Alain GUILLEMOT <alain.guillemot@asn.com>
Cc : libc-help@sourceware.org
Objet : Re: Glibc on target 32 bits with 64-bit time support

* Alain GUILLEMOT: > In which file I have to add the option "-D_FILE_OFFSET_BITS=64 > -D_TIME_BITS=64", or are these options to be passed on the command > line? All ABI variants are automatically built. You don't have to do anything


* Alain GUILLEMOT:



> In which file I have to add the option "-D_FILE_OFFSET_BITS=64

> -D_TIME_BITS=64", or are these options to be passed on the command

> line?



All ABI variants are automatically built.  You don't have to do anything

while building glibc.  These flags are for building applications with

glibc.



Thanks,

Florian

Re: Glibc on target 32 bits with 64-bit time support

[Florian Weimer]

* Alain GUILLEMOT:

> In « glibc-2.34/configure » file, for “ CFLAGS="-g -O2
> -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64"” and CXXFLAGS, and with
> CPPFLAGS environment variable.

Sorry, what is your question?

Thanks,
Florian

RE: Glibc on target 32 bits with 64-bit time support

[Alain GUILLEMOT]

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Hi Florian

OK, that means that since glibc 2.34, glibc automatically recognizes whether the time_t structure is 32 or 64 bits.

 And therefore only the applications must be recompiled with the flags "-D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64" ).


This is correct ?


De : Florian Weimer <fweimer@redhat.com>
Envoyé : lundi 15 mai 2023 22:12
À : Alain GUILLEMOT <alain.guillemot@asn.com>
Cc : libc-help@sourceware.org
Objet : Re: Glibc on target 32 bits with 64-bit time support

* Alain GUILLEMOT: > In which file I have to add the option "-D_FILE_OFFSET_BITS=64 > -D_TIME_BITS=64", or are these options to be passed on the command > line? All ABI variants are automatically built. You don't have to do anything


* Alain GUILLEMOT:



> In which file I have to add the option "-D_FILE_OFFSET_BITS=64

> -D_TIME_BITS=64", or are these options to be passed on the command

> line?



All ABI variants are automatically built.  You don't have to do anything

while building glibc.  These flags are for building applications with

glibc.



Thanks,

Florian

Re: Glibc on target 32 bits with 64-bit time support

[Lukasz Majewski]

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Hi Alain,

> Hi Florian
> 
> OK, that means that since glibc 2.34, glibc automatically recognizes
> whether the time_t structure is 32 or 64 bits.
> 
>  And therefore only the applications must be recompiled with the
> flags "-D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64" ).
> 
> 
> This is correct ?

In principle yes.

Please find some extra information regarding glibc integration with 64
bit time support.

https://github.com/lmajewski/meta-y2038#readme

> 
> 
> De : Florian Weimer <fweimer@redhat.com>
> Envoyé : lundi 15 mai 2023 22:12
> À : Alain GUILLEMOT <alain.guillemot@asn.com>
> Cc : libc-help@sourceware.org
> Objet : Re: Glibc on target 32 bits with 64-bit time support
> 
> * Alain GUILLEMOT: > In which file I have to add the option
> "-D_FILE_OFFSET_BITS=64 > -D_TIME_BITS=64", or are these options to
> be passed on the command > line? All ABI variants are automatically
> built. You don't have to do anything
> 
> 
> * Alain GUILLEMOT:
> 
> 
> 
> > In which file I have to add the option "-D_FILE_OFFSET_BITS=64  
> 
> > -D_TIME_BITS=64", or are these options to be passed on the command  
> 
> > line?  
> 
> 
> 
> All ABI variants are automatically built.  You don't have to do
> anything
> 
> while building glibc.  These flags are for building applications with
> 
> glibc.
> 
> 
> 
> Thanks,
> 
> Florian
> 
> 




Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Erika Unter
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de

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RE: Glibc on target 32 bits with 64-bit time support

[Alain GUILLEMOT]

Thank's for the answer, I will test it next week.

A+

-----Message d'origine-----
De : Lukasz Majewski <lukma@denx.de> 
Envoyé : jeudi 18 mai 2023 12:47
À : Alain GUILLEMOT <alain.guillemot@asn.com>
Cc : Florian Weimer <fweimer@redhat.com>; libc-help@sourceware.org
Objet : Re: Glibc on target 32 bits with 64-bit time support

Hi Alain,

> Hi Florian
> 
> OK, that means that since glibc 2.34, glibc automatically recognizes 
> whether the time_t structure is 32 or 64 bits.
> 
>  And therefore only the applications must be recompiled with the flags 
> "-D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64" ).
> 
> 
> This is correct ?

In principle yes.

Please find some extra information regarding glibc integration with 64 bit time support.

https://urldefense.com/v3/__https://github.com/lmajewski/meta-y2038*readme__;Iw!!HqwE!OnXimeUXo9KINuxtprxS7lYTXshhXz0xlRq3nBN_xR8FktKu9dTiEthPRSULKfz-5PbSfmtj0NvSWjUN$ 

> 
> 
> De : Florian Weimer <fweimer@redhat.com> Envoyé : lundi 15 mai 2023 
> 22:12 À : Alain GUILLEMOT <alain.guillemot@asn.com> Cc : 
> libc-help@sourceware.org Objet : Re: Glibc on target 32 bits with 
> 64-bit time support
> 
> * Alain GUILLEMOT: > In which file I have to add the option
> "-D_FILE_OFFSET_BITS=64 > -D_TIME_BITS=64", or are these options to be 
> passed on the command > line? All ABI variants are automatically 
> built. You don't have to do anything
> 
> 
> * Alain GUILLEMOT:
> 
> 
> 
> > In which file I have to add the option "-D_FILE_OFFSET_BITS=64
> 
> > -D_TIME_BITS=64", or are these options to be passed on the command
> 
> > line?  
> 
> 
> 
> All ABI variants are automatically built.  You don't have to do 
> anything
> 
> while building glibc.  These flags are for building applications with
> 
> glibc.
> 
> 
> 
> Thanks,
> 
> Florian
> 
> 




Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Erika Unter
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de