perl EV module on Android 10 (terminal emulator)

[Marc Lehmann]

On Sat, Jun 05, 2021 at 11:06:43AM -0400, AC <achirvasub at gmail.com> wrote:
> I am running the Termux[0] terminal emulator on an Android 10 phone (aarch64), with perl v5.32.1.

Hi! Many apologies, but your mail seemed to be stuck in mailman for an
extended period of time :/, or I just didn't see it for soem reason.

> $ perl -MEV
> 
> EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}? at /data/data/com.termux/files/usr/lib/perl5/site_perl/5.32.1/aarch64-android/EV.pm line 1245.
> Compilation failed in require.
> BEGIN failed--compilation aborted.

> I have also tried exporting LIBEV_FLAGS to 0, 1, 2 or 3 to no effect.
> 
> How could I debug this further, to get to the root of the matter?

My first guess would be that no backends are enabled, which is quite likely
in your environment:

First, the select backend is disabled on __ANDROID (because the header
files on android are not good enough) - maybe, if termux provides an
environment different to android, it should not define that symbol (it
currently defines it).

Similarly, Ev might have trouble autodetecting other backends, in which case
you should enable them manually.

In fact, I tried it out right now, and when I enable poll and epoll
manually, the testsuite passes. You can provide the configuration using an
env variable, for automatic builds, e.g.:

export EV_EXTRA_DEFS="-DEV_USE_POLL=1 -DEV_USE_EPOLL=1 -DEV_USE_INOTIFY=1 -DEV_USE_EVENTFD=1"

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