diff --git a/addons/cppcheckdata.py b/addons/cppcheckdata.py
index 0258b18fb..78c6bdd79 100755
--- a/addons/cppcheckdata.py
+++ b/addons/cppcheckdata.py
@@ -341,6 +341,7 @@ class Function:
         tokenDef                Token in function definition
         isVirtual               Is this function is virtual
         isImplicitlyVirtual     Is this function is virtual this in the base classes
+        isStatic                Is this function is static
     """
 
     Id = None
@@ -352,6 +353,7 @@ class Function:
     type = None
     isVirtual = None
     isImplicitlyVirtual = None
+    isStatic = None
 
     def __init__(self, element):
         self.Id = element.get('id')
@@ -362,6 +364,8 @@ class Function:
         self.isVirtual = (isVirtual and isVirtual == 'true')
         isImplicitlyVirtual = element.get('isImplicitlyVirtual')
         self.isImplicitlyVirtual = (isImplicitlyVirtual and isImplicitlyVirtual == 'true')
+        isStatic = element.get('isStatic')
+        self.isStatic = (isStatic and isStatic == 'true')
 
         self.argument = {}
         self.argumentId = {}
diff --git a/addons/misra.py b/addons/misra.py
index 4da7fb462..3a137ad8d 100755
--- a/addons/misra.py
+++ b/addons/misra.py
@@ -1937,6 +1937,38 @@ class MisraChecker:
                     ifStack.pop()
 
 
+    def misra_21_1(self, data):
+        # Reference: n1570 7.1.3 - Reserved identifiers
+        re_forbidden_macro = re.compile(r'#define (errno|_[_A-Z]+)')
+
+        # Search for forbidden identifiers in macro names
+        for directive in data.directives:
+            res = re.search(re_forbidden_macro, directive.str)
+            if res:
+                self.reportError(directive, 21, 1)
+
+        # Search for forbidden identifiers
+        for token in data.tokenlist:
+            if not token.isName:
+                continue
+            if len(token.str) < 2:
+                continue
+            if token.str == 'errno':
+                self.reportError(token, 21, 1)
+            if token.str[0] == '_':
+                if (token.str[1] in string.ascii_uppercase) or (token.str[1] == '_'):
+                    self.reportError(token, 21, 1)
+
+                # Allow identifiers with file scope visibility (static)
+                if token.scope.type == 'Global':
+                    if token.variable and token.variable.isStatic:
+                        continue
+                    if token.function and token.function.isStatic:
+                        continue
+
+                self.reportError(token, 21, 1)
+
+
     def misra_21_3(self, data):
         for token in data.tokenlist:
             if isFunctionCall(token) and (token.astOperand1.str in ('malloc', 'calloc', 'realloc', 'free')):
@@ -1998,6 +2030,20 @@ class MisraChecker:
             self.reportError(directive, 21, 11)
 
 
+    def misra_21_12(self, data):
+        if findInclude(data.directives, '<fenv.h>'):
+            for token in data.tokenlist:
+                if token.str == 'fexcept_t' and token.isName:
+                    self.reportError(token, 21, 12)
+                if isFunctionCall(token) and (token.astOperand1.str in (
+                    'feclearexcept',
+                    'fegetexceptflag',
+                    'feraiseexcept',
+                    'fesetexceptflag',
+                    'fetestexcept')):
+                    self.reportError(token, 21, 12)
+
+
     def get_verify_expected(self):
         """Return the list of expected violations in the verify test"""
         return self.verify_expected
@@ -2495,6 +2541,7 @@ class MisraChecker:
             self.misra_20_10(cfg)
             self.misra_20_13(cfg)
             self.misra_20_14(cfg)
+            self.misra_21_1(cfg)
             self.misra_21_3(cfg)
             self.misra_21_4(cfg)
             self.misra_21_5(cfg)
@@ -2504,6 +2551,7 @@ class MisraChecker:
             self.misra_21_9(cfg)
             self.misra_21_10(cfg)
             self.misra_21_11(cfg)
+            self.misra_21_12(cfg)
             # 22.4 is already covered by Cppcheck writeReadOnlyFile
 
 
diff --git a/addons/test/misra/misra-test.c b/addons/test/misra/misra-test.c
index 4bd51c5f5..ed80f2ce3 100644
--- a/addons/test/misra/misra-test.c
+++ b/addons/test/misra/misra-test.c
@@ -11,6 +11,7 @@
 #include <wchar.h> //21.6
 #include <time.h> // 21.10
 #include <tgmath.h> // 21.11
+#include <fenv.h>
 
 
 typedef unsigned char      u8;
@@ -395,7 +396,7 @@ void misra_14_2() {
 struct {
   unsigned int x:1;
   unsigned int y:1;
-} _14_4_struct;
+} r14_4_struct;
 void misra_14_4(bool b) {
   if (x+4){} // 14.4
   else {}
@@ -403,7 +404,7 @@ void misra_14_4(bool b) {
   if (b) {}
   else {}
 
-  if (_14_4_struct.x) {}
+  if (r14_4_struct.x) {}
 }
 
 void misra_15_1() {
@@ -652,12 +653,12 @@ struct {
     } nested_2;
     uint8_t data_3[]; // 18.7
   } nested_3;
-} _18_7_struct;
+} r18_7_struct;
 struct {
   uint16_t len;
   uint8_t data_1[ 19 ];
   uint8_t data_2[   ]; // 18.7
-} _18_7_struct;
+} r18_7_struct;
 
 void misra_18_8(int x) {
   int buf1[10];
@@ -688,6 +689,58 @@ union misra_19_2 { }; // 19.2
 # def fun_2013(v) () // 20.13
 #endif
 
+#define _Incompatible 0xdeadbeef // 21.1
+#define __Incompatible 0xdeadbeef // 21.1
+#define __starts_with_lower 0xdeadbeef // 21.1
+#define __MY_HEADER_ // 21.1
+#define _starts_with_lower 1 // no warning
+static int _file_scope_id_21_1 = 42; // no warning
+static int _file_scope_id_21_1_fn() { return 42; } // no warning
+static int __file_scope_id_21_1 = 42; // 21.1
+static int __file_scope_id_21_1_fn() { return 42; } // 21.1
+static int _File_scope_id_21_1 = 42; // 21.1
+static int _File_scope_id_21_1_fn() { return 42; } // 21.1
+int _external_scope_id_21_1 = 42; // 21.1
+int _external_scope_id_21_1_fn() { return 42; } // 21.1
+int __external_scope_id_21_1 = 42; // 21.1
+int __external_scope_id_21_1_fn() { return 42; } // 21.1
+int _External_scope_id_21_1 = 42; // 21.1
+int _External_scope_id_21_1_fn() { return 42; } // 21.1
+int errno = 42; // 21.1
+int errno() { // 21.1
+    // TODO: 15.5 false positive
+    return 42; // 15.5
+}
+
+struct _struct_21_1 { int a; }; // 21.1
+struct _Struct_21_1 { int a; }; // 21.1
+struct __struct_21_1 { int a; }; // 21.1
+typedef struct { int a; } _struct_21_1_t; // 21.1
+typedef struct { int a; } _Struct_21_1_t; // 21.1
+typedef struct { int a; } __struct_21_1_t; // 21.1
+
+enum _enum_21_1 { ENUM211_1 }; // 21.1
+enum _Enum_21_1 { ENUM211_2 }; // 21.1
+enum __enum_21_1 { ENUM211_3 }; // 21.1
+enum __enum_21_1 { ENUM211_3 }; // 21.1
+typedef enum { ENUM211_4 } _enum_21_1_t; // 21.1
+typedef enum { ENUM211_5 } _Enum_21_1_t; // 21.1
+typedef enum { ENUM211_6 } __enum_21_1_t; // 21.1
+enum enum_21_1_valid_id {
+    ENUM211_7,
+    _ENUM211_8, // 21.1
+    __ENUM211_9, // 21.1
+    _eNUM211_10, // 21.1
+    enum211_11
+};
+
+union _union_21_1 { int a; }; // 21.1 19.2
+union _Union_21_1 { int a; }; // 21.1 19.2
+union __union_21_1 { int a; }; // 21.1 19.2
+typedef union { int a; } _union_21_1_t; // 21.1 19.2
+typedef union { int a; } _Union_21_1_t; // 21.1 19.2
+typedef union { int a; } __union_21_1_t; // 21.1 19.2
+
 void misra_21_3() {
   p1=malloc(10); // 21.3
   p2=calloc(10); // 21.3
@@ -713,3 +766,14 @@ void misra_21_9() {
   (void)bsearch(key,base,num,size,cmp); // 21.9
   qsort(base,num,size,cmp); // 21.9
 }
+
+void misra_21_12() {
+    int rc;
+    fexcept_t f; // 21.12
+    rc = feclearexcept(1); // 21.12
+    rc = fegetexceptflag(&f, 1); // 21.12
+    rc = feraiseexcept(1); // 21.12
+    rc = fesetexceptflag(&f, 1); // 21.12
+    rc = fetestexcept(1); // 21.12
+}
+
diff --git a/lib/symboldatabase.cpp b/lib/symboldatabase.cpp
index 1b5b82d9a..4b5985e3e 100644
--- a/lib/symboldatabase.cpp
+++ b/lib/symboldatabase.cpp
@@ -3225,6 +3225,8 @@ void SymbolDatabase::printXml(std::ostream &out) const
                         else if (function->isImplicitlyVirtual())
                             out << " isImplicitlyVirtual=\"true\"";
                     }
+                    if (function->isStatic())
+                        out << " isStatic=\"true\"";
                     if (function->argCount() == 0U)
                         out << "/>" << std::endl;
                     else {
diff --git a/test/testsymboldatabase.cpp b/test/testsymboldatabase.cpp
index 23299e3e6..ebaaafe4e 100644
--- a/test/testsymboldatabase.cpp
+++ b/test/testsymboldatabase.cpp
@@ -221,6 +221,8 @@ private:
 
         TEST_CASE(functionImplicitlyVirtual);
 
+        TEST_CASE(functionStatic);
+
         TEST_CASE(namespaces1);
         TEST_CASE(namespaces2);
         TEST_CASE(namespaces3);  // #3854 - unknown macro
@@ -2287,6 +2289,14 @@ private:
         ASSERT_EQUALS(true, function && function->isImplicitlyVirtual(false));
     }
 
+    void functionStatic() {
+        GET_SYMBOL_DB("static void fs() {  }");
+        (void)db;
+        const Function *func = db->scopeList.back().function;
+        ASSERT(func);
+        ASSERT(func->isStatic());
+    }
+
     void namespaces1() {
         GET_SYMBOL_DB("namespace fred {\n"
                       "    namespace barney {\n"