static ARGC: Atomic<isize>Available on AIX or Android or Cygwin or DragonFly BSD or Emscripten or FreeBSD or Fuchsia or GNU/Hurd or Haiku or Hermit or Horizon or illumos or L4Re or Linux or NetBSD or NuttX or OpenBSD or QNX SDP 7.x or QNX SDP 8.0+ or Redox OS or RTEMS OS or Solaris or VxWorks only.