Updated code to determine capture card tuning capabilities

Replaced macro-based code that determines the capture card tuning capabilities
and that gives messages about the presence or absence of these capabilities
with more verbose and less obfuscated code.
No functional changes.

mythtv/libs/libmythtv/recorders/dvbsignalmonitor.cpp

@@ -90,27 +90,60 @@ DVBSignalMonitor::DVBSignalMonitor(int db_cardnum, DVBChannel* _channel,
     // in practice, however this is correct for the 4.0 DVB API
     m_signalStrength.SetRange(0, 65535);
 
+    // Determine the signal monitoring capabilities from the card and
+    // do not use the capabilities that are not present.
     uint64_t rmflags = 0;
 
-// NOLINTNEXTLINE(cppcoreguidelines-macro-usage)
-#define DVB_IO(FLAG, METHOD, MSG) \
-  do { if (HasFlags(FLAG)) { bool mok; _channel->METHOD(&mok); \
-          if (!mok) { \
-              LOG(VB_GENERAL, LOG_WARNING, LOC+"Cannot "+(MSG)+ENO); \
-              rmflags |= (FLAG); } \
-          else { \
-              LOG(VB_CHANNEL, LOG_INFO, LOC + "Can " + (MSG)); } } } while (false)
-
-    DVB_IO(kSigMon_WaitForSig, GetSignalStrength,
-           "measure Signal Strength");
-    DVB_IO(kDVBSigMon_WaitForSNR, GetSNR,
-           "measure S/N");
-    DVB_IO(kDVBSigMon_WaitForBER, GetBitErrorRate,
-           "measure Bit Error Rate");
-    DVB_IO(kDVBSigMon_WaitForUB, GetUncorrectedBlockCount,
-           "count Uncorrected Blocks");
-
-#undef DVB_IO
+    auto log_message = [](bool ok, QString loc, QString msg)
+    { 
+        if (ok)
+            LOG(VB_CHANNEL, LOG_INFO, loc + "Can " + msg);
+        else
+            LOG(VB_GENERAL, LOG_WARNING, loc + "Cannot " + msg + ENO);
+    };
+
+    auto update_rmflags = [&](bool ok, uint64_t flag)
+    {
+        if (!ok)
+            rmflags |= flag;
+    };
+
+    // Signal strength
+    auto flag = kSigMon_WaitForSig;
+    bool mok;
+    if (HasFlags(flag))
+    {
+        _channel->GetSignalStrength(&mok);
+        update_rmflags(mok, flag);
+        log_message(mok, LOC, "measure Signal Strength");
+    }
+
+    // Signal/Noise ratio
+    flag = kDVBSigMon_WaitForSNR;
+    if (HasFlags(flag))
+    {
+        _channel->GetSNR(&mok);
+        update_rmflags(mok, flag);
+        log_message(mok, LOC, "measure S/N");
+    }
+
+    // Bit error rate
+    flag = kDVBSigMon_WaitForBER;
+    if (HasFlags(flag))
+    {
+        _channel->GetBitErrorRate(&mok);
+        update_rmflags(mok, flag);
+        log_message(mok, LOC, "measure Bit Error Rate");
+    }
+
+    // Uncorrected block count
+    flag = kDVBSigMon_WaitForUB;
+    if (HasFlags(flag))
+    {
+        _channel->GetUncorrectedBlockCount(&mok);
+        update_rmflags(mok, flag);
+        log_message(mok, LOC, "count Uncorrected Blocks");
+    }
 
     RemoveFlags(rmflags);