Why is this an issue?
C++17 introduced std::byte. It allows you to have byte-oriented access to a memory in a type-safe unambiguous manner. Before, you had to use either
char, signed char, or unsigned char to access memory as bytes. The previous approach is error-prone as
char type allows you to accidentally perform arithmetic operations. Also, it is confusing since char, signed
char, and unsigned char are also used to represent actual characters and arithmetic values.
std::byte is simply a scoped enumeration with bit-wise operators and a helper function to_integer<T> to convert
byte object to integral type T.
This rule will detect byte-like usage of char, signed char, and unsigned char and suggest replacing them by
std::byte.
Noncompliant code example
void handleFirstByte(char* byte);
void f(int* i) {
char* c = reinterpret_cast<char*>(i); // Noncompliant
handleFirstByte(c);
}
unsigned char negate(unsigned char byte) {
return ~byte; // Noncompliant
}
Compliant solution
void handleFirstByte(std::byte* byte);
void f(int* i) {
std::byte* byte = reinterpret_cast<std::byte*>(i); // Compliant
handleFirstByte(byte);
}
std::byte negate(std::byte byte) {
return ~byte; // Compliant
}
