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What is a valid function template overloading

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A function template can be overloaded under the rules for non-template function overloading (same name, but different parameter types) and in addition to that, the overloading is valid if

For a normal function, comparing two parameter types is is easy for the compiler, since it has all informat. But a type within a template may not be determined yet. Therefore, the rule for when two parameter types are equal is approximative here and says that the non-depependend types and values need to match and the spelling of dependent types and expressions needs to be the same (more precisely, they need to conform to the so-called ODR-rules), except that template parameters may be renamed. However, if under such different spellings, two values within the types are deemed different, but will always instantiate to the same values, the overloading is invalid, but no diagnostic is required from the compiler. 

template<typename T>
void f(T*) { }

template<typename T>
void f(T) { }

This is a valid overload, as “T” and “T*” are different spellings. But the following is invalid, with no diagnostic required 

template<typename T>
void f(T (*x)[sizeof(T) + sizeof(T)]) { }

template<typename T>
void f(T (*x)[2 * sizeof(T)]) { }
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Function template overloading:
* Function Template Overloading
* What is a valid function template overloading
Table Of Contents
0 Getting started
1 Literals
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33 std::function
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35 std::iomanip
36 Iterators
37 Basic I/O
38 File I/O
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42 Returning multiple values from a function
43 References
44 Polymorphism
45 Value and reference semantics
46 Function call by value vs. by reference
47 Copying vs assignment
48 Pointers to class / struct members
49 The this pointer
50 Smart pointers
51 Unions
52 Templates
53 Namespaces
54 Function overloading
55 Operator overloading
56 Lambdas
57 Threading
58 Value categories
59 Preprocessor
60 SFINAE
61 Rule of three, five and zero
62 RAII
63 Exceptions
64 Implementation-defined behavior
65 Special member functions
66 Random numbers
67 Sorting
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69 Perfect forwarding
70 Virtual member functions
71 Undefined behavior
72 Overload resolution
73 Move semantics
74 Pimpl idiom
75 Copy elision
76 Fold expressions
77 Unnamed types
78 Singleton
79 ISO C++ Standard
80 User-defined literals
81 Type erasure
82 Memory management
83 Explicit type conversions
84 RTTI
85 Standard library algorithms
86 Expression templates
87 Scopes
88 Atomic types
89 static assert
90 constexpr
91 Date and time with std::chrono
92 Trailing return type
93 Function template overloading
94 Common compile linker errors
95 Design patterns
96 Optimizations
97 Compiling and building
98 Type traits
99 One definition rule
100 Unspecified behavio
101 Argument dependent name lookup
102 Attributes
103 Internationalization
104 Profiling
105 Return type covariance
106 Non-static member functions
107 Recursion
108 Callable objects
109 Constant class member functions
110 C++ vs. C++ 11 vs C++ 17
111 Inline functions
112 Client server examples
113 Header files
114 Const correctness
115 Refactoring techniques
116 Parameter packs
117 Iteration
118 type deduction
119 C++ 11 memory model
120 Build systems
121 Concurrency with OpenMP
122 Type inference
123 Resource management
124 Storage class specifiers
125 Alignment
126 Inline variables
127 Linkage specifications
128 Curiusly recurring template pattern
129 Using declaration
130 Typedef and type aliases
131 Layout of object types
132 C incompatibilities
133 Optimization
134 Semaphore
135 Thread synchronization
136 Debugging
137 Futures and promises
138 More undefined behaviors
139 Mutexes
140 Recursive mutex
141 Unit testing
142 decltype
143 Digit separators
144 C++ Containers
145 Arithmetic meta-programming
146 Contributors