diff --git a/include/nlohmann/detail/input/input_adapters.hpp b/include/nlohmann/detail/input/input_adapters.hpp
index 98249774..3c097a6a 100644
--- a/include/nlohmann/detail/input/input_adapters.hpp
+++ b/include/nlohmann/detail/input/input_adapters.hpp
@@ -53,17 +53,17 @@ Input adapter for stdio file access. This adapter read only 1 byte and do not us
 class file_input_adapter : public input_adapter_protocol
 {
   public:
-    explicit file_input_adapter(FILE* file)  noexcept
-        : file(file)
+    explicit file_input_adapter(std::FILE* f)  noexcept
+        : m_file(f)
     {}
 
     std::char_traits<char>::int_type get_character() noexcept override
     {
-        return fgetc(file);
+        return std::fgetc(m_file);
     }
   private:
     /// the file pointer to read from
-    FILE* file;
+    std::FILE* m_file;
 };
 
 
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 93ed2b24..781d6f14 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -2102,17 +2102,17 @@ Input adapter for stdio file access. This adapter read only 1 byte and do not us
 class file_input_adapter : public input_adapter_protocol
 {
   public:
-    explicit file_input_adapter(FILE* file)  noexcept
-        : file(file)
+    explicit file_input_adapter(std::FILE* f)  noexcept
+        : m_file(f)
     {}
 
     std::char_traits<char>::int_type get_character() noexcept override
     {
-        return fgetc(file);
+        return std::fgetc(m_file);
     }
   private:
     /// the file pointer to read from
-    FILE* file;
+    std::FILE* m_file;
 };
 
 
diff --git a/test/src/unit-testsuites.cpp b/test/src/unit-testsuites.cpp
index fe3e0175..9563b498 100644
--- a/test/src/unit-testsuites.cpp
+++ b/test/src/unit-testsuites.cpp
@@ -386,35 +386,35 @@ TEST_CASE("json.org examples")
     }
     SECTION("FILE 1.json")
     {
-        std::unique_ptr<FILE, decltype(&fclose)> f(fopen("test/data/json.org/1.json", "r"), &fclose);
+        std::unique_ptr<std::FILE, decltype(&std::fclose)> f(std::fopen("test/data/json.org/1.json", "r"), &std::fclose);
         json j;
         CHECK_NOTHROW(j.parse(f.get()));
     }
 
     SECTION("FILE 2.json")
     {
-        std::unique_ptr<FILE, decltype(&fclose)> f(fopen("test/data/json.org/2.json", "r"), &fclose);
+        std::unique_ptr<std::FILE, decltype(&std::fclose)> f(std::fopen("test/data/json.org/2.json", "r"), &std::fclose);
         json j;
         CHECK_NOTHROW(j.parse(f.get()));
     }
 
     SECTION("FILE 3.json")
     {
-        std::unique_ptr<FILE, decltype(&fclose)> f(fopen("test/data/json.org/3.json", "r"), &fclose);
+        std::unique_ptr<std::FILE, decltype(&std::fclose)> f(std::fopen("test/data/json.org/3.json", "r"), &std::fclose);
         json j;
         CHECK_NOTHROW(j.parse(f.get()));
     }
 
     SECTION("FILE 4.json")
     {
-        std::unique_ptr<FILE, decltype(&fclose)> f(fopen("test/data/json.org/4.json", "r"), &fclose);
+        std::unique_ptr<std::FILE, decltype(&std::fclose)> f(std::fopen("test/data/json.org/4.json", "r"), &std::fclose);
         json j;
         CHECK_NOTHROW(j.parse(f.get()));
     }
 
     SECTION("FILE 5.json")
     {
-        std::unique_ptr<FILE, decltype(&fclose)> f(fopen("test/data/json.org/5.json", "r"), &fclose);
+        std::unique_ptr<std::FILE, decltype(&std::fclose)> f(std::fopen("test/data/json.org/5.json", "r"), &std::fclose);
         json j;
         CHECK_NOTHROW(j.parse(f.get()));
     }