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Author: dl8sd11

clang-tools-extra/clang-tidy/portability/AvoidPragmaOnceCheck.h

@@ -24,7 +24,7 @@ class AvoidPragmaOnceCheck : public ClangTidyCheck {
   AvoidPragmaOnceCheck(StringRef Name, ClangTidyContext *Context)
       : ClangTidyCheck(Name, Context) {}
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
-    return LangOpts.CPlusPlus;
+    return LangOpts.CPlusPlus || LangOpts.C99;
   }
 
   void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,

clang-tools-extra/docs/clang-tidy/checks/portability/avoid-pragma-once.rst

@@ -13,7 +13,7 @@ some environments.
 Some older or specialized C/C++ compilers, particularly in embedded systems,
 may not fully support ``#pragma once``.
 
-Also it can fail in certain file system configurations,like network drives
+It can also fail in certain file system configurations,like network drives
 or complex symbolic links, potentially leading to compilation issues.
 
 Consider the following header file:
@@ -22,3 +22,14 @@ Consider the following header file:
 
   // my_header.h
   #pragma once // warning: avoid 'pragma once' directive; use include guards instead
+
+
+The warning suggests using include guards:
+
+.. code:: c++
+
+  // my_header.h
+  #ifndef PATH_TO_MY_HEADER_H
+  #define PATH_TO_MY_HEADER_H
+
+  #endif // PATH_TO_MY_HEADER_H