22 General utilities library [utilities]

22.14 Formatting [format]

22.14.2 Format string [format.string] Standard format specifiers [format.string.std]

Table 72: Meaning of type options for pointer types [tab:format.type.ptr]
none, p
If uintptr_t is defined, to_chars(first, last, reinterpret_cast<uintptr_t>(value), 16) with the prefix 0x inserted immediately before the output of to_chars; otherwise, implementation-defined.
The same as p, except that it uses uppercase letters for digits above 9 and the base prefix is 0X.