There are 2 variants of strerror_r, GNU extension and a POSIX variant.
Use the more portable POSIX variant.
Also fix a potensial stack-use-after-return bug, instead of relying on
undefined behavoir in GNU libc implementation. The strerror_r manpage
says:
> This may be either a pointer to a string that the function stores in
> buf, or a pointer to some (immutable) static string (in which case buf
> is unused).
So it does not guarantee that it returns a pointer to some (immutable)
static string. It might return a pointer to "buf", in which case we get
a stack-use-after-return bug.
We fix this by declaring a thread local static buffer which we always
return.
If BUILD_IPV6=ON (default), but the user has disabled ipv6 support
in the kernel using the parameter ipv6.disable=1, then conky fails
to open /proc/net/if_inet6. This leads to a segfault when conky
calls fclose(file) regardless. This fix simply moves the fclose call
into the preceding if statement.
In our XCreateWindow call, we always set the backing_store attribute
to 'Always'. But since we never add the CWBackingStore to our value
mask, the backing_store setting always gets set to the default
NotUseful. This means that the backing store is never turned on, and
so when unobscuring the conky window, portions of the display will not
be drawn immediately if conky is blocked doing something else (e.g.
network, disk, the process is stopped), which is really annoying.
To fix this, specify the CWBackingStore flag in our value mask, so the
conky data is always visible, even if conky is blocking on some other
operation.
x11 shape extension (version >= 1.1) provide ability to set up input region
set up empty input region for undecorated window to create transparent window for mouse events
It now reports only reclaimable memory, by excluding shared memory,
and including the reclaimable part of the SLAB cache.
So '$mem' with 'no_buffers yes' is now the "really used" (unreclaimable) memory.
And when reaching OOM conditions, conky will always report high memory usage.
Related post:
http://calimeroteknik.free.fr/blag/?article20/really-used-memory-on-gnu-linux
In particular:
- Don't call get_battery_perct() recursively.
- Use define for length of string holding battery name.
- We can use strcpy() since bat is zero-terminated.
