Re: [PATCH 1/2] configure: detect 64 bit time_t

[Tomi Ollila <tomi.ollila@iki.fi>]

On Wed, Jun 24 2020, David Bremner wrote:

> Certain tests involving timestamps > 32bits cannot pass with the
> current libnotmuch API. We will avoid this isssue for now by disabling

s/isssue/issue/

> those tests on "old" architectures with 32bit time_t.
> ---
>  configure | 33 ++++++++++++++++++++++++++++++++-
>  1 file changed, 32 insertions(+), 1 deletion(-)
>
> diff --git a/configure b/configure
> index 05ade05b..ecb0bdb7 100755
> --- a/configure
> +++ b/configure
> @@ -1045,6 +1045,34 @@ else
>  fi
>  rm -f compat/have_timegm
>  
> +cat <<EOF > _time_t.c
> +#include <time.h>
> +#include <stdio.h>
> +int main(int argc, char**argv) {
> +  printf("%d\n",sizeof(time_t) >= 8);

Since notmuch now (since fall 2018) requires c11 compiler, static_assert
would be simpler alternative:

    #include <assert.h>
    #include <time.h>

    static_assert(sizeof(time_t) >= 8, "sizeof(time_t) < 8");

and

    if ${CC} -c _time_t.c -o /dev/null > /dev/null 2>&1
    then 
         printf "Yes.\n"
         have_64bit_time_t=1
    else 
         printf "No.\n"
         have_64bit_time_t=0
    fi

but if not... 

> +}
> +EOF
> +
> +printf "Checking for 64 bit time_t... "
> +if ${CC} _time_t.c -o _time_t > /dev/null 2>&1;
> +then
> +    have_64bit_time_t=$(./_time_t)

anyway would be better for _time_t just exit 0 or 1 and
set have_64bit_time_t as (inverse =D) of that (like above),
... but still, static_assert FTW \0/ ;)

> +    if [ $have_64bit_time_t -eq 1 ]
> +    then
> +        printf "Yes.\n"
> +    else
> +        printf "No.\n"
> +    fi
> +else
> +    cat <<EOF
> +
> +*** Error: compilation failed.  Please try running configure again in
> +a clean environment, and if the problem persists, report a bug.
> +EOF
> +    rm -f _time_t _time_t.c exit 1
> +fi
> +
> +
>  printf "Checking for dirent.d_type... "
>  if ${CC} -o compat/have_d_type "$srcdir"/compat/have_d_type.c > /dev/null 2>&1
>  then
> @@ -1128,7 +1156,7 @@ for flag in -Wmissing-declarations; do
>  done
>  printf "\n\t%s\n" "${WARN_CFLAGS}"
>  
> -rm -f minimal minimal.c _libversion.c _libversion _libversion.sh _check_session_keys.c _check_session_keys _check_x509_validity.c _check_x509_validity
> +rm -f minimal minimal.c _time_t _time_t.c _libversion.c _libversion _libversion.sh _check_session_keys.c _check_session_keys _check_x509_validity.c _check_x509_validity
>  
>  # construct the Makefile.config
>  cat > Makefile.config <<EOF
> @@ -1429,6 +1457,9 @@ NOTMUCH_HAVE_MAN=$((have_sphinx))
>  NOTMUCH_HAVE_BASH=${have_bash}
>  NOTMUCH_BASH_ABSOLUTE=${bash_absolute}
>  
> +# Whether time_t is 64 bits (or more)
> +NOTMUCH_HAVE_64BIT_TIME_T=${have_64bit_time_t}
> +
>  # Whether perl exists, and if so where
>  NOTMUCH_HAVE_PERL=${have_perl}
>  NOTMUCH_PERL_ABSOLUTE=${perl_absolute}
> -- 
> 2.27.0