According to range based for loop documentation here:

begin_expr and end_expr are defined as follows:

• If range_expression is an expression of array type, then begin_expr is __range and end_expr is (__range + __bound), where __bound is the number of elements in the array (if the array has unknown size or is of an incomplete type, the program is ill-formed)
• If range_expression is an expression of a class type C that has a member named begin and/or a member named end (regardless of the type or accessibility of such member), then begin_expr is __range.begin) and end_expr is __range.end();
• Otherwise, begin_expr is begin(__range) and end_expr is end(__range), which are found via argument-dependent lookup (non-ADL lookup is not performed).

However, if I define begin() and end() for a pointer type, it fails to work.

Example

#include <iostream>

using LPCSTR = char const*;

LPCSTR begin(LPCSTR str)
{
    return str;
}

LPCSTR end(LPCSTR str)
{
    return str + strlen(str);
}

int main()
{
    LPCSTR text = "Hello, world!\n";
    for (auto c : text)
    {
        std::cout << c;
    }
}

Error(s):

source_file.cpp:18:17: error: invalid range expression of type 'const char *'; no viable 'begin' function available
    for (auto c : text)
                ^ ~~~~
1 error generated.

Demo

I don't see any reference that pointers are excluded from the ADL, so what reason would there be as to why this isn't working?