Re: [ptxdist] [PATCH] libtahu: Change CFLAGS to use 64-bit system time

[Ian Abbott <abbotti@mev.co.uk>]

On 23/02/2023 15:42, Michael Olbrich wrote:
> On Mon, Feb 20, 2023 at 01:41:05PM +0000, Ian Abbott wrote:
>> libtahu exposes a library function `get_current_timestamp()` to return
>> the real-time clock as the number of milliseconds since the Unix epoch
>> as a 64-bit value.  It calls `clock_gettime(CLOCK_REALTIME, &ts)` (where
>> `ts` is a `struct timespec`) to get the system time and does some simple
>> arithmetic on `ts.tv_sec` and `ts.tv_nsec` to convert the time to a
>> number of milliseconds.
>>
>> Ideally, we want `ts.tv_sec` to have a 64-bit type to avoid Y2038
>> problems, but on most 32-bit architectures, `ts.tv_sec` will have a
>> 32-bit type by default.  Try and select the 64-bit time interface even
>> on 32-bit architectures by appending `-D_FILE_OFFSET_BITS=64` and
>> `-D_TIME_BITS=64` to the `CFLAGS` variable when invoking `make`.  This
>> works for glibc 2.34 or later when the system is running on Linux kernel
>> 5.1 or later.
>>
>> Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
>> ---
>>   rules/libtahu.make | 5 +++--
>>   1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/rules/libtahu.make b/rules/libtahu.make
>> index 26c064c6d..3e392216d 100644
>> --- a/rules/libtahu.make
>> +++ b/rules/libtahu.make
>> @@ -37,11 +37,12 @@ LIBTAHU_CONF_TOOL	:= NO
>>   # Compile
>>   # ----------------------------------------------------------------------------
>>   
>> -#LIBTAHU_MAKE_ENV	:= $(CROSS_ENV)
>> -
>> +LIBTAHU_CPPFLAGS := -Iinclude -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64
>> +LIBTAHU_CFLAGS := -O2 -g -g3 -fPIC
> 
> No need to mess with the existing CFLAGS. You can inject extra CFLAGS
> though the toolchain wrappers. And for correctness, make it conditional:
> 
> ifdef PTXCONF_GLOBAL_LARGE_FILE
> LIBTAHU_CFLAGS := -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64
> endif
> 
> nothing else is needed.
> 
> Michael

Hi Michael,

Sorry to be a pain.  I'm attempting to inject extra CFLAGS through the 
toolchain wrappers, but I'm not sure how to do it.  Here is one of my 
attempts that does not work:

# 
----------------------------------------------------------------------------
# Prepare
# 
----------------------------------------------------------------------------

LIBTAHU_CONF_TOOL	:= NO

# 
----------------------------------------------------------------------------
# Compile
# 
----------------------------------------------------------------------------

# -D_TIME_BITS=64 requires -D_FILE_OFFSET_BITS=64
LIBTAHU_CPPFLAGS := -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64
LIBTAHU_CFLAGS := -O2
LIBTAHU_MAKE_ENV := $(CROSS_ENV)
# Just build the dynamic library.
LIBTAHU_MAKE_OPT := \
	$(CROSS_ENV_PROGS) \
	lib/libtahu.so

$(STATEDIR)/libtahu.compile:
	@$(call targetinfo)
	@$(call world/compile, LIBTAHU)
	@$(call touch)

I'm obviously missing something to pass the properly wrapped CC and CPP 
variables (incorporating the extra flags) to 'make'.  Could you provide 
a clue how to fix it?

Thanks

Ian

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