function pleac_Making_Variables_Private_to_a_Function()
{
// Strictly-speaking, PHP is neither lexically [no environment capture] nor
// dynamically [no variable shadowing] scoped. A script in which several
// functions have been defined has two, entirely separate, scopes:
//
// * A 'top-level' scope i.e. everything outside each function
//
// * A 'local scope' within each function; each function is a self-contained
// entity and cannot [via conventional means] access variables outside its
// local scope. Accessing a variable that has not been locally defined
// serves to define it i.e. accessing a variable assumed to be global
// sees a local variable of that name defined
//
// The way 'global' variables are provided is via a predefined array of
// variable names, $GLOBALS [it is one of a special set of variables known
// as 'superglobals'; such variables *are* accessable in all scopes]. Each
// entry in this array is a 'global' variable name, and may be freely
// accessed / updated. A more convenient means of accessing such variables
// is via the 'global' keyword: one or more variables within a function is
// declared 'global', and those names are then taken to refer to entries
// in the $GLOBALS array rather than seeing local variables of that name
// accessed or defined
function some_func()
{
// Variables declared within a function are local to that function
$variable = 'something';
}
// ----------------------------
// Top-level declared variables
$name = $argv[1];
$age = $argv[2];
$c = fetch_time();
$condition = 0;
// ------------
function run_check()
{
// The globally-declared variable, '$condition', is not accessable within
// the function unless it declared as 'global. Had this not been done then
// attempts to access, '$condition', would have seen a local variable
// of that name declared and updated. Same applies to other variables
global $condition, $name, $age, $c;
$condition = 1;
// ...
}
function check_x($x)
{
$y = 'whatever';
// This function only has access to the parameter, '$x', and the locally
// declared variable, '$y'.
// Whilst 'run_check' has access to several global variables, the current
// function does not. For it to access the global variable, '$condition',
// it must be declared 'global'
run_check();
global $condition;
// 'run_check' will have updated, '$condition', and since it has been
// declared 'global' here, it is accessable
if ($condition) {
// ...
}
}
}
function store_data()
{
$cookie = fetch_cookie();
# Validated for certain safety measures.
$ua_id = get_ua();
$tokens = param_val("tokens", "/^[:_a-zA-Z0-9 ,-]+\$/");
global $dbhandle;
$sql = sprintf("REPLACE INTO survey (\n status_a, \n status_aaaa,\n status_ds4,\n status_ds6,\n status_ipv4,\n status_ipv6,\n status_v6ns,\n status_v6mtu,\n status_dsmtu,\n \n time_a,\n time_aaaa,\n time_ds4,\n time_ds6,\n time_ipv4,\n time_ipv6,\n time_v6ns,\n time_v6mtu,\n time_dsmtu,\n \n tokens,\n ua_id,\n \n cookie, ip, ip4, ip6\n \n )\n VALUES ('%s','%s','%s','%s','%s','%s','%s','%s','%s',\n '%s','%s','%s','%s','%s','%s','%s','%s','%s',\n '%s','%s',\n '%s','%s','%s','%s')", mysql_real_escape_string(fetch_status("a"), $dbhandle), mysql_real_escape_string(fetch_status("aaaa"), $dbhandle), mysql_real_escape_string(fetch_status("ds4"), $dbhandle), mysql_real_escape_string(fetch_status("ds6"), $dbhandle), mysql_real_escape_string(fetch_status("ipv4"), $dbhandle), mysql_real_escape_string(fetch_status("ipv6"), $dbhandle), mysql_real_escape_string(fetch_status("v6ns"), $dbhandle), mysql_real_escape_string(fetch_status("v6mtu"), $dbhandle), mysql_real_escape_string(fetch_status("dsmtu"), $dbhandle), mysql_real_escape_string(fetch_time("a"), $dbhandle), mysql_real_escape_string(fetch_time("aaaa"), $dbhandle), mysql_real_escape_string(fetch_time("ds4"), $dbhandle), mysql_real_escape_string(fetch_time("ds6"), $dbhandle), mysql_real_escape_string(fetch_time("ipv4"), $dbhandle), mysql_real_escape_string(fetch_time("ipv6"), $dbhandle), mysql_real_escape_string(fetch_time("v6ns"), $dbhandle), mysql_real_escape_string(fetch_time("v6mtu"), $dbhandle), mysql_real_escape_string(fetch_time("dsmtu"), $dbhandle), mysql_real_escape_string($tokens, $dbhandle), mysql_real_escape_string($ua_id, $dbhandle), mysql_real_escape_string($cookie, $dbhandle), mysql_real_escape_string(remote_addr(), $dbhandle), mysql_real_escape_string(fetch_addr("ip4"), $dbhandle), mysql_real_escape_string(fetch_addr("ip6"), $dbhandle));
# print $sql;
$result = mysql_query($sql, $dbhandle);
if (!$result) {
$message = 'Invalid query: ' . mysql_error() . "\n";
$message .= 'Whole query: ' . $sql;
die($message);
}
# header("HTTP/1.0 204 No Content");
}