diff --git a/cxx/mount_pz.h b/cxx/mount_pz.h
index a176666..0513067 100644
--- a/cxx/mount_pz.h
+++ b/cxx/mount_pz.h
@@ -214,6 +214,50 @@ private:
 };
 
 
+class MccNearMeridianPZ
+{
+public:
+    MccNearMeridianPZ(const MccAngle& delta_az) : _deltaAZ(delta_az)
+    {
+        _deltaAZ.normalize();  // to [0, 360)
+    }
+
+    std::string_view name() const
+    {
+        return "NEAR-MERIDIAN-LIMIT";
+    }
+
+    std::string_view desc() const
+    {
+        return "Near-meridian prohibited zone";
+    }
+
+    bool inZone(const MccAngle& x, const MccAngle& y, const MccProhibitedZone::pzcontext_t& context)
+    {
+        if (context.coords_kind == MccProhibitedZone::COORDS_KIND_AZALT) {  // trivial case
+        }
+
+        return false;
+    }
+
+    auto timeTo(const MccAngle& x,
+                const MccAngle& y,
+                const MccProhibitedZone::pzcontext_t& context,
+                traits::mcc_systime_c auto const& utc = std::chrono::system_clock::now())
+    {
+    }
+
+    auto timeFrom(const MccAngle& x,
+                  const MccAngle& y,
+                  const MccProhibitedZone::pzcontext_t& context,
+                  traits::mcc_systime_c auto const& utc = std::chrono::system_clock::now())
+    {
+    }
+
+private:
+    MccAngle _deltaAZ;
+};
+
 /*
  * a general planar ellipse equation:
  *     A*(x-xc)^2 + B*(x-xc)(y-yc) + C*(y-yc)^2 = 1
diff --git a/cxx/utils.h b/cxx/utils.h
index 7ca2839..d97131e 100644
--- a/cxx/utils.h
+++ b/cxx/utils.h
@@ -285,4 +285,11 @@ static std::string AZZD_rad2sxg(double az, double zd, std::string_view delim = "
 }
 
 
+static bool isEqual(std::floating_point auto const& v1, std::floating_point auto const& v2)
+{
+    constexpr auto eps = std::numeric_limits<std::common_type_t<decltype(v1), decltype(v2)>>::epsilon();
+
+    return std::fabs(v1 - v2) <= eps * std::fmax(std::fabs(v1), std::fabs(v2));
+}
+
 }  // namespace mcc::utils