(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
pg_lo_read_all — 读入整个大型对象并直接发送给浏览器
$large_object
) : int
pg_lo_read_all() 读入一个大型对象并在（PHP）发送完所有待发的 header 之后将其直接发送给浏览器。主要目的是发送图片或声音等二进制数据。返回值为读入的字节数，如果出错则返回 false。
要使用大型对象（lo）接口，需要将其放置在事务块中。
Note:
本函数以前的名字为
pg_loreadall()。
参见 pg_lo_read()。
Pay attention that if you omit the "length" parameter it will read a 8192 bytes object regardless to its real dimensions. If you want to use this function think to save the object size somewhere (usually a field in its table) before reading the object. Alternatively use the pg_lo_readall function.
// remember, large objects must be obtained from within a transaction
pg_query ($dbconn, "begin");
// "assume" for this example that the large object resource number of the zipped file is "17899"
$lo_oid = 17899;
$handle_lo = pg_lo_open($dbconn,$lo_oid,"r") or die("<h1>Error.. can't get handle</h1>");
//headers to send to the browser before beginning the binary download
header('Accept-Ranges: bytes');
header('Content-Length: 32029974'); //this is the size of the zipped file
header('Keep-Alive: timeout=15, max=100');
header('Content-type: Application/x-zip');
header('Content-Disposition: attachment; filename="superjob.zip"');
pg_lo_read_all($handle_lo) or
die("<h1>Error, can't read large object.</h1>");
// committing the data transaction
pg_query ($dbconn, "commit");