diff --git a/include/verilated.cpp b/include/verilated.cpp
index 34f715952..d842d16ce 100644
--- a/include/verilated.cpp
+++ b/include/verilated.cpp
@@ -688,10 +688,11 @@ std::string _vl_vsformat_time(char* tmp, double ld, bool left, size_t width) {
     QData fraction = static_cast<QData>(scaled) % fracDiv;
     int digits = 0;
     if (!fracDigits) {
-        digits = sprintf(tmp, "%" VL_PRI64 "u%s", whole, suffix.c_str());
+        digits = VL_SNPRINTF(tmp, VL_VALUE_STRING_MAX_WIDTH, "%" VL_PRI64 "u%s", whole,
+                             suffix.c_str());
     } else {
-        digits = sprintf(tmp, "%" VL_PRI64 "u.%0*" VL_PRI64 "u%s", whole, fracDigits, fraction,
-                         suffix.c_str());
+        digits = VL_SNPRINTF(tmp, VL_VALUE_STRING_MAX_WIDTH, "%" VL_PRI64 "u.%0*" VL_PRI64 "u%s",
+                             whole, fracDigits, fraction, suffix.c_str());
     }
     int needmore = width - digits;
     std::string padding;
@@ -791,7 +792,7 @@ void _vl_vsformat(std::string& output, const char* formatp, va_list ap) VL_MT_SA
                     output += _vl_vsformat_time(t_tmp, d, left, width);
                 } else {
                     std::string fmts(pctp, pos - pctp + 1);
-                    sprintf(t_tmp, fmts.c_str(), d);
+                    VL_SNPRINTF(t_tmp, VL_VALUE_STRING_MAX_WIDTH, fmts.c_str(), d);
                     output += t_tmp;
                 }
                 break;
@@ -836,8 +837,9 @@ void _vl_vsformat(std::string& output, const char* formatp, va_list ap) VL_MT_SA
                     int digits = 0;
                     std::string append;
                     if (lbits <= VL_QUADSIZE) {
-                        digits = sprintf(t_tmp, "%" VL_PRI64 "d",
-                                         static_cast<vlsint64_t>(VL_EXTENDS_QQ(lbits, lbits, ld)));
+                        digits = VL_SNPRINTF(
+                            t_tmp, VL_VALUE_STRING_MAX_WIDTH, "%" VL_PRI64 "d",
+                            static_cast<vlsint64_t>(VL_EXTENDS_QQ(lbits, lbits, ld)));
                         append = t_tmp;
                     } else {
                         if (VL_SIGN_E(lbits, lwp[VL_WORDS_I(lbits) - 1])) {
@@ -865,7 +867,8 @@ void _vl_vsformat(std::string& output, const char* formatp, va_list ap) VL_MT_SA
                     int digits = 0;
                     std::string append;
                     if (lbits <= VL_QUADSIZE) {
-                        digits = sprintf(t_tmp, "%" VL_PRI64 "u", ld);
+                        digits
+                            = VL_SNPRINTF(t_tmp, VL_VALUE_STRING_MAX_WIDTH, "%" VL_PRI64 "u", ld);
                         append = t_tmp;
                     } else {
                         append = VL_DECIMAL_NW(lbits, lwp);
@@ -1671,9 +1674,11 @@ const char* vl_mc_scan_plusargs(const char* prefixp) VL_MT_SAFE {
     const std::string& match = VerilatedImp::argPlusMatch(prefixp);
     static VL_THREAD_LOCAL char t_outstr[VL_VALUE_STRING_MAX_WIDTH];
     if (match.empty()) return nullptr;
-    t_outstr[0] = '\0';
-    strncat(t_outstr, match.c_str() + strlen(prefixp) + 1,  // +1 to skip the "+"
-            VL_VALUE_STRING_MAX_WIDTH - 1);
+    char* dp = t_outstr;
+    for (const char* sp = match.c_str() + strlen(prefixp) + 1;  // +1 to skip the "+"
+         *sp && (dp - t_outstr) < (VL_VALUE_STRING_MAX_WIDTH - 2);)
+        *dp++ = *sp++;
+    *dp++ = '\0';
     return t_outstr;
 }
 
@@ -2346,14 +2351,16 @@ const char* Verilated::catName(const char* n1, const char* n2, const char* delim
     static VL_THREAD_LOCAL char* t_strp = nullptr;
     static VL_THREAD_LOCAL size_t t_len = 0;
     size_t newlen = strlen(n1) + strlen(n2) + strlen(delimiter) + 1;
-    if (!t_strp || newlen > t_len) {
+    if (VL_UNLIKELY(!t_strp || newlen > t_len)) {
         if (t_strp) delete[] t_strp;
         t_strp = new char[newlen];
         t_len = newlen;
     }
-    strcpy(t_strp, n1);
-    if (*n1) strcat(t_strp, delimiter);
-    strcat(t_strp, n2);
+    char* dp = t_strp;
+    for (const char* sp = n1; *sp;) *dp++ = *sp++;
+    for (const char* sp = delimiter; *sp;) *dp++ = *sp++;
+    for (const char* sp = n2; *sp;) *dp++ = *sp++;
+    *dp++ = '\0';
     return t_strp;
 }
 
@@ -2396,7 +2403,7 @@ void Verilated::runFlushCallbacks() VL_MT_SAFE {
 #ifdef VL_THREADED
     static std::atomic<int> s_recursing;
 #else
-    int s_recursing = 0;
+    static int s_recursing = 0;
 #endif
     if (!s_recursing++) {
         const VerilatedLockGuard lock(VlCbStatic.s_flushMutex);
@@ -2423,7 +2430,7 @@ void Verilated::runExitCallbacks() VL_MT_SAFE {
 #ifdef VL_THREADED
     static std::atomic<int> s_recursing;
 #else
-    int s_recursing = 0;
+    static int s_recursing = 0;
 #endif
     if (!s_recursing++) {
         const VerilatedLockGuard lock(VlCbStatic.s_exitMutex);
@@ -2446,8 +2453,10 @@ const char* Verilated::commandArgsPlusMatch(const char* prefixp) VL_MT_SAFE {
     const std::string& match = VerilatedImp::argPlusMatch(prefixp);
     static VL_THREAD_LOCAL char t_outstr[VL_VALUE_STRING_MAX_WIDTH];
     if (match.empty()) return "";
-    t_outstr[0] = '\0';
-    strncat(t_outstr, match.c_str(), VL_VALUE_STRING_MAX_WIDTH - 1);
+    char* dp = t_outstr;
+    for (const char* sp = match.c_str(); *sp && (dp - t_outstr) < (VL_VALUE_STRING_MAX_WIDTH - 2);)
+        *dp++ = *sp++;
+    *dp++ = '\0';
     return t_outstr;
 }
 
@@ -2712,11 +2721,15 @@ void VerilatedScope::configure(VerilatedSyms* symsp, const char* prefixp, const
     m_symsp = symsp;
     m_type = type;
     m_timeunit = timeunit;
-    char* namep = new char[strlen(prefixp) + strlen(suffixp) + 2];
-    strcpy(namep, prefixp);
-    if (*prefixp && *suffixp) strcat(namep, ".");
-    strcat(namep, suffixp);
-    m_namep = namep;
+    {
+        char* namep = new char[strlen(prefixp) + strlen(suffixp) + 2];
+        char* dp = namep;
+        for (const char* sp = prefixp; *sp;) *dp++ = *sp++;
+        if (*prefixp && *suffixp) *dp++ = '.';
+        for (const char* sp = suffixp; *sp;) *dp++ = *sp++;
+        *dp++ = '\0';
+        m_namep = namep;
+    }
     m_identifierp = identifier;
     VerilatedImp::scopeInsert(this);
 }
diff --git a/include/verilated_cov.cpp b/include/verilated_cov.cpp
index 8a7c9bdaf..377d5abbe 100644
--- a/include/verilated_cov.cpp
+++ b/include/verilated_cov.cpp
@@ -134,7 +134,7 @@ private:
         for (const char* pos = text.c_str(); *pos; ++pos) {
             if (!isprint(*pos) || *pos == '%' || *pos == '"') {
                 char hex[10];
-                sprintf(hex, "%%%02X", pos[0]);
+                VL_SNPRINTF(hex, 10, "%%%02X", pos[0]);
                 rtn += hex;
             } else {
                 rtn += *pos;
diff --git a/include/verilated_trace_imp.cpp b/include/verilated_trace_imp.cpp
index fe4580794..aa4a6c233 100644
--- a/include/verilated_trace_imp.cpp
+++ b/include/verilated_trace_imp.cpp
@@ -70,7 +70,7 @@ static std::string doubleToTimescale(double value) {
     else if (value >= 1e-18) { suffixp = "as"; value *= 1e18; }
     // clang-format on
     char valuestr[100];
-    sprintf(valuestr, "%0.0f%s", value, suffixp);
+    VL_SNPRINTF(valuestr, 100, "%0.0f%s", value, suffixp);
     return valuestr;  // Gets converted to string, so no ref to stack
 }
 
diff --git a/include/verilated_vcd_c.cpp b/include/verilated_vcd_c.cpp
index c59468167..c379b678a 100644
--- a/include/verilated_vcd_c.cpp
+++ b/include/verilated_vcd_c.cpp
@@ -269,7 +269,7 @@ void VerilatedVcd::printStr(const char* str) {
 
 void VerilatedVcd::printQuad(vluint64_t n) {
     char buf[100];
-    sprintf(buf, "%" VL_PRI64 "u", n);
+    VL_SNPRINTF(buf, 100, "%" VL_PRI64 "u", n);
     printStr(buf);
 }
 
@@ -347,9 +347,16 @@ void VerilatedVcd::printIndent(int level_change) {
 
 void VerilatedVcd::dumpHeader() {
     printStr("$version Generated by VerilatedVcd $end\n");
-    time_t time_str = time(nullptr);
     printStr("$date ");
-    printStr(ctime(&time_str));
+    {
+        time_t tick = time(nullptr);
+        tm ticktm;
+        VL_LOCALTIME_R(&tick, &ticktm);
+        constexpr int bufsize = 50;
+        char buf[bufsize];
+        strftime(buf, bufsize, "%c", &ticktm);
+        printStr(buf);
+    }
     printStr(" $end\n");
 
     printStr("$timescale ");
@@ -487,11 +494,12 @@ void VerilatedVcd::declare(vluint32_t code, const char* name, const char* wirep,
         decl += wirep;  // usually "wire"
     }
 
-    char buf[1000];
-    sprintf(buf, " %2d ", bits);
+    constexpr size_t bufsize = 1000;
+    char buf[bufsize];
+    VL_SNPRINTF(buf, bufsize, " %2d ", bits);
     decl += buf;
     if (m_evcd) {
-        sprintf(buf, "<%u", code);
+        VL_SNPRINTF(buf, bufsize, "<%u", code);
         decl += buf;
     } else {
         // Add string code to decl
@@ -505,7 +513,8 @@ void VerilatedVcd::declare(vluint32_t code, const char* name, const char* wirep,
         // 1 bit values don't have a ' ' separator between value and string code
         const bool isBit = bits == 1;
         entryp[0] = ' ';  // Separator
-        std::strcpy(entryp + !isBit, buf);  // Code (overwrite separator if isBit)
+        // Use memcpy as we checked size above, and strcpy is flagged unsafe
+        std::memcpy(entryp + !isBit, buf, strlen(buf));  // Code (overwrite separator if isBit)
         entryp[length + !isBit] = '\n';  // Replace '\0' with line termination '\n'
         // Set length of suffix (used to increment write pointer)
         entryp[VL_TRACE_SUFFIX_ENTRY_SIZE - 1] = !isBit + length + 1;
@@ -513,12 +522,12 @@ void VerilatedVcd::declare(vluint32_t code, const char* name, const char* wirep,
     decl += " ";
     decl += basename;
     if (array) {
-        sprintf(buf, "(%d)", arraynum);
+        VL_SNPRINTF(buf, bufsize, "(%d)", arraynum);
         decl += buf;
         hiername += buf;
     }
     if (bussed) {
-        sprintf(buf, " [%d:%d]", msb, lsb);
+        VL_SNPRINTF(buf, bufsize, " [%d:%d]", msb, lsb);
         decl += buf;
     }
     decl += " $end\n";
@@ -656,8 +665,8 @@ void VerilatedVcd::emitWData(vluint32_t code, const WData* newvalp, int bits) {
 VL_ATTR_ALWINLINE
 void VerilatedVcd::emitDouble(vluint32_t code, double newval) {
     char* wp = m_writep;
-    // Buffer can't overflow before sprintf; we sized during declaration
-    sprintf(wp, "r%.16g", newval);
+    // Buffer can't overflow before VL_SNPRINTF; we sized during declaration
+    VL_SNPRINTF(wp, m_wrChunkSize, "r%.16g", newval);
     wp += strlen(wp);
     finishLine(code, wp);
 }
@@ -770,8 +779,8 @@ void VerilatedVcd::fullTriArray(vluint32_t code, const vluint32_t* newvalp,
 void VerilatedVcd::fullDouble(vluint32_t code, const double newval) {
     // cppcheck-suppress invalidPointerCast
     (*(reinterpret_cast<double*>(oldp(code)))) = newval;
-    // Buffer can't overflow before sprintf; we sized during declaration
-    sprintf(m_writep, "r%.16g", newval);
+    // Buffer can't overflow before VL_SNPRINTF; we sized during declaration
+    VL_SNPRINTF(m_writep, m_wrChunkSize, "r%.16g", newval);
     m_writep += strlen(m_writep);
     *m_writep++ = ' ';
     m_writep = writeCode(m_writep, code);
diff --git a/include/verilated_vpi.cpp b/include/verilated_vpi.cpp
index 7b25337e6..6814e819e 100644
--- a/include/verilated_vpi.cpp
+++ b/include/verilated_vpi.cpp
@@ -336,8 +336,8 @@ public:
     virtual const VerilatedRange* rangep() const override { return &(varp()->packed()); }
     virtual const char* fullname() const override {
         static VL_THREAD_LOCAL std::string t_out;
-        char num[20];
-        sprintf(num, "%d", m_index);
+        char num[25];
+        VL_SNPRINTF(num, 25, "%d", m_index);
         t_out = std::string(scopep()->name()) + "." + name() + "[" + num + "]";
         return t_out.c_str();
     }
diff --git a/include/verilatedos.h b/include/verilatedos.h
index 55be76d6e..abd61195f 100644
--- a/include/verilatedos.h
+++ b/include/verilatedos.h
@@ -481,7 +481,7 @@ typedef unsigned long long vluint64_t;  ///< 64-bit unsigned type
 #endif
 
 //=========================================================================
-// String related OS-specific functions
+// String/time related OS-specific functions
 
 #ifdef _MSC_VER
 # define VL_STRCASECMP _stricmp
@@ -489,6 +489,12 @@ typedef unsigned long long vluint64_t;  ///< 64-bit unsigned type
 # define VL_STRCASECMP strcasecmp
 #endif
 
+#ifdef _MSC_VER
+# define VL_LOCALTIME_R(timep, tmp) localtime_c((tmp), (timep))
+#else
+# define VL_LOCALTIME_R(timep, tmp) localtime_r((timep), (tmp))
+#endif
+
 //=========================================================================
 // Macros controlling target specific optimizations
 
diff --git a/src/V3Ast.cpp b/src/V3Ast.cpp
index 31f0b4d42..7be1e7a4d 100644
--- a/src/V3Ast.cpp
+++ b/src/V3Ast.cpp
@@ -120,9 +120,9 @@ string AstNode::encodeName(const string& namein) {
             // We also do *NOT* use __DOT__ etc, as we search for those
             // in some replacements, and don't want to mangle the user's names.
             unsigned val = pos[0] & 0xff;  // Mask to avoid sign extension
-            char hex[10];
-            sprintf(hex, "__0%02X", val);
-            out += hex;
+            std::stringstream hex;
+            hex << std::setfill('0') << std::setw(2) << std::hex << val;
+            out += "__0" + hex.str();
         }
     }
     // Shorten names
diff --git a/src/V3File.cpp b/src/V3File.cpp
index a9be42ed6..fbcd02eac 100644
--- a/src/V3File.cpp
+++ b/src/V3File.cpp
@@ -873,9 +873,7 @@ string V3OutFormatter::quoteNameControls(const string& namein, V3OutFormatter::L
             } else if (isprint(c)) {
                 out += c;
             } else {
-                char decimal[10];
-                sprintf(decimal, "&#%u;", (unsigned char)c);
-                out += decimal;
+                out += string("&#") + cvtToStr((unsigned int)(c & 0xff)) + ";";
             }
         }
     } else {
@@ -893,9 +891,8 @@ string V3OutFormatter::quoteNameControls(const string& namein, V3OutFormatter::L
                 out += c;
             } else {
                 // This will also cover \a etc
-                // Can't use %03o as messes up when signed
-                char octal[10];
-                sprintf(octal, "\\%o%o%o", (c >> 6) & 3, (c >> 3) & 7, c & 7);
+                string octal = string("\\") + cvtToStr((c >> 6) & 3) + cvtToStr((c >> 3) & 7)
+                               + cvtToStr(c & 7);
                 out += octal;
             }
         }
@@ -907,10 +904,11 @@ string V3OutFormatter::quoteNameControls(const string& namein, V3OutFormatter::L
 // Simple wrappers
 
 void V3OutFormatter::printf(const char* fmt...) {
-    char sbuff[5000];
+    constexpr size_t bufsize = 5000;
+    char sbuff[bufsize];
     va_list ap;
     va_start(ap, fmt);
-    vsprintf(sbuff, fmt, ap);
+    VL_VSNPRINTF(sbuff, bufsize, fmt, ap);
     va_end(ap);
     this->puts(sbuff);
 }
diff --git a/src/V3FileLine.cpp b/src/V3FileLine.cpp
index 5fae3ce6a..de02e9026 100644
--- a/src/V3FileLine.cpp
+++ b/src/V3FileLine.cpp
@@ -165,11 +165,8 @@ string FileLine::xmlDetailedLocation() const {
 }
 
 string FileLine::lineDirectiveStrg(int enterExit) const {
-    char numbuf[20];
-    sprintf(numbuf, "%d", lastLineno());
-    char levelbuf[20];
-    sprintf(levelbuf, "%d", enterExit);
-    return (string("`line ") + numbuf + " \"" + filename() + "\" " + levelbuf + "\n");
+    return std::string("`line ") + cvtToStr(lastLineno()) + " \"" + filename() + "\" "
+           + cvtToStr(enterExit) + "\n";
 }
 
 void FileLine::lineDirective(const char* textp, int& enterExitRef) {
diff --git a/src/V3Global.cpp b/src/V3Global.cpp
index 73115a7b3..73e78711a 100644
--- a/src/V3Global.cpp
+++ b/src/V3Global.cpp
@@ -80,6 +80,18 @@ void V3Global::readFiles() {
     }
 }
 
+string V3Global::debugFilename(const string& nameComment, int newNumber) {
+    ++m_debugFileNumber;
+    if (newNumber) m_debugFileNumber = newNumber;
+    return opt.hierTopDataDir() + "/" + opt.prefix() + "_" + digitsFilename(m_debugFileNumber)
+           + "_" + nameComment;
+}
+string V3Global::digitsFilename(int number) {
+    std::stringstream ss;
+    ss << std::setfill('0') << std::setw(3) << number;
+    return ss.str();
+}
+
 void V3Global::dumpCheckGlobalTree(const string& stagename, int newNumber, bool doDump) {
     v3Global.rootp()->dumpTreeFile(v3Global.debugFilename(stagename + ".tree", newNumber), false,
                                    doDump);
diff --git a/src/V3Global.h b/src/V3Global.h
index f2b028038..693b213a3 100644
--- a/src/V3Global.h
+++ b/src/V3Global.h
@@ -140,13 +140,8 @@ public:
     void widthMinUsage(const VWidthMinUsage& flag) { m_widthMinUsage = flag; }
     bool constRemoveXs() const { return m_constRemoveXs; }
     void constRemoveXs(bool flag) { m_constRemoveXs = flag; }
-    string debugFilename(const string& nameComment, int newNumber = 0) {
-        ++m_debugFileNumber;
-        if (newNumber) m_debugFileNumber = newNumber;
-        char digits[100];
-        sprintf(digits, "%03d", m_debugFileNumber);
-        return opt.hierTopDataDir() + "/" + opt.prefix() + "_" + digits + "_" + nameComment;
-    }
+    string debugFilename(const string& nameComment, int newNumber = 0);
+    static string digitsFilename(int number);
     bool needHeavy() const { return m_needHeavy; }
     void needHeavy(bool flag) { m_needHeavy = flag; }
     bool needTraceDumper() const { return m_needTraceDumper; }
diff --git a/src/V3Number.cpp b/src/V3Number.cpp
index 91a52ece2..b6bd7937b 100644
--- a/src/V3Number.cpp
+++ b/src/V3Number.cpp
@@ -696,7 +696,7 @@ string V3Number::displayed(FileLine* fl, const string& vformat) const {
     case 'g':
     case '^': {  // Realtime
         char tmp[MAX_SPRINTF_DOUBLE_SIZE];
-        sprintf(tmp, vformat.c_str(), toDouble());
+        VL_SNPRINTF(tmp, MAX_SPRINTF_DOUBLE_SIZE, vformat.c_str(), toDouble());
         return tmp;
     }
     // 'l'   // Library - converted to text by V3LinkResolve
diff --git a/src/V3PreLex.l b/src/V3PreLex.l
index dbe22e3f6..f1c37cd94 100644
--- a/src/V3PreLex.l
+++ b/src/V3PreLex.l
@@ -125,8 +125,8 @@ bom             [\357\273\277]
                           rtnfile += '"'; yytext = (char*)rtnfile.c_str(); yyleng = rtnfile.length();
                           return VP_STRING; }
 <INITIAL,STRIFY>"`__LINE__"     { FL_FWDC;
-                          static char buf[10];
-                          sprintf(buf, "%d", LEXP->curFilelinep()->lastLineno());
+                          static char buf[25];
+                          VL_SNPRINTF(buf, 25, "%d", LEXP->curFilelinep()->lastLineno());
                           yytext = buf; yyleng = strlen(yytext);
                           return VP_TEXT; }
 
diff --git a/src/V3StatsReport.cpp b/src/V3StatsReport.cpp
index 0eb3b9961..530a06901 100644
--- a/src/V3StatsReport.cpp
+++ b/src/V3StatsReport.cpp
@@ -208,9 +208,7 @@ void V3Stats::statsStage(const string& name) {
     static double lastWallTime = -1;
     static int fileNumber = 0;
 
-    char digits[100];
-    sprintf(digits, "%03d", ++fileNumber);
-    const string digitName = string(digits) + "_" + name;
+    const string digitName = V3Global::digitsFilename(++fileNumber) + "_" + name;
 
     double wallTime = V3Os::timeUsecs() / 1.0e6;
     if (lastWallTime < 0) lastWallTime = wallTime;
diff --git a/test_regress/t/t_dpi_open_elem_c.cpp b/test_regress/t/t_dpi_open_elem_c.cpp
index 72a8793a4..01ee72427 100644
--- a/test_regress/t/t_dpi_open_elem_c.cpp
+++ b/test_regress/t/t_dpi_open_elem_c.cpp
@@ -83,7 +83,6 @@ static void _dpii_bit_elem_ux(int p, int u, const svOpenArrayHandle i, const svO
 #ifndef NC
     // NC always returns zero and warns
     CHECK_RESULT_HEX(dim, u);
-    // svSizeOfArray(i) undeterministic as not in C representation
 #endif
 
     for (int a = svLow(i, 1); a <= svHigh(i, 1); ++a) {
@@ -135,13 +134,14 @@ void dpii_bit_elem_p0_u3(int p, int u, const svOpenArrayHandle i, const svOpenAr
 
 static void _dpii_logic_elem_ux(int p, int u, const svOpenArrayHandle i, const svOpenArrayHandle o,
                                 const svOpenArrayHandle q) {
-    int sizeInputOfArray = svSizeOfArray(i);
     int dim = svDimensions(i);
 #ifndef NC
     // NC always returns zero and warns
     CHECK_RESULT_HEX(dim, u);
-    // svSizeOfArray(i) undeterministic as not in C representation
 #endif
+    int sizeInputOfArray = svSizeOfArray(i);
+    // svSizeOfArray(i) undeterministic as not in C representation
+    if (sizeInputOfArray) {}
 
     for (int a = svLow(i, 1); a <= svHigh(i, 1); ++a) {
         if (dim == 1) {
diff --git a/test_regress/t/t_dpi_open_oob_bad_c.cpp b/test_regress/t/t_dpi_open_oob_bad_c.cpp
index 5ed9853c0..ddd9e821a 100644
--- a/test_regress/t/t_dpi_open_oob_bad_c.cpp
+++ b/test_regress/t/t_dpi_open_oob_bad_c.cpp
@@ -107,9 +107,13 @@ void dpii_int_u3(const svOpenArrayHandle i) {
     CHECK_RESULT_HEX_NE(ip, 0);
     // Out of bounds
     ip = (intptr_t)svGetArrElemPtr3(i, 1, 2, 30);
+    CHECK_RESULT_HEX(ip, 0);
     ip = (intptr_t)svGetArrElemPtr3(i, 1, 20, 3);
+    CHECK_RESULT_HEX(ip, 0);
     ip = (intptr_t)svGetArrElemPtr3(i, 10, 2, 3);
+    CHECK_RESULT_HEX(ip, 0);
     ip = (intptr_t)svGetArrElemPtr1(i, 30);
+    CHECK_RESULT_HEX(ip, 0);
 }
 
 void dpii_real_u1(const svOpenArrayHandle i) {
diff --git a/test_regress/t/t_vpi_var.cpp b/test_regress/t/t_vpi_var.cpp
index d9ec774b2..9ddd720e2 100644
--- a/test_regress/t/t_vpi_var.cpp
+++ b/test_regress/t/t_vpi_var.cpp
@@ -498,7 +498,7 @@ int _mon_check_putget_str(p_cb_data cb_data) {
     static TestVpiHandle cb;
     static struct {
         TestVpiHandle scope, sig, rfr, check, verbose;
-        char str[128 + 1];  // char per bit plus null terminator
+        std::string str;
         int type;  // value type in .str
         union {
             PLI_INT32 integer;
@@ -532,10 +532,10 @@ int _mon_check_putget_str(p_cb_data cb_data) {
                 vpi_get_value(data[i].sig, &v);
                 TEST_MSG("%s\n", v.value.str);
                 if (data[i].type) {
-                    CHECK_RESULT_CSTR(v.value.str, data[i].str);
+                    CHECK_RESULT_CSTR(v.value.str, data[i].str.c_str());
                 } else {
                     data[i].type = v.format;
-                    strcpy(data[i].str, v.value.str);
+                    data[i].str = std::string(v.value.str);
                 }
             }
 
@@ -556,7 +556,7 @@ int _mon_check_putget_str(p_cb_data cb_data) {
             if (callback_count_strs & 7) {
                 // put same value back - checking encoding/decoding equivalent
                 v.format = data[i].type;
-                v.value.str = data[i].str;
+                v.value.str = (PLI_BYTE8*)(data[i].str.c_str());  // Can't reinterpret_cast
                 vpi_put_value(data[i].sig, &v, &t, vpiNoDelay);
                 v.format = vpiIntVal;
                 v.value.integer = 1;