Initialize a variable

Compilers get confused when variables are initialized by a function by
taking them as reference in an out argument; this, coupled with the fact
that C does not initialize variables by default, most commonly results
in a "maybe uninitialized" compiler warning.
8 jobs for unused-warning in 18 minutes and 40 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #219117
cross-android_api21_arm64

00:01:02

passed #219118
cross-android_api28_arm64

00:01:01

passed #219119
cross-mingw64

00:02:22

passed #219116
fedora-x86_64

00:04:41

passed #219122
freebsd-11
freebsd-11-x86_64

00:03:43

passed #219120
win32
msys2-mingw32

00:11:40

passed #219121
win32
vs2017-x64

00:07:37

 
  Coverage
passed #219123
coverage

00:02:16

74.5%