[Konstantinos]

It is only valid if name contains A-Z, a-z characters and 1 underscore:

pawn Код:

IsValidRPName(const p_name[])
{
    new count_underscore;
    for (new i, j = strlen(p_name); i != j; i++)
    {
        switch (p_name[i])
        {
            case 'A' .. 'Z', 'a' .. 'z': continue;
            case '_': count_underscore++;
            default: return 0;
        }
    }
    return count_underscore == 1;
}