SplFileObject::fgets

Notice that the behavior of fgets after a seek changed on PHP 8.0.10, if you seek to line 50 and run fgets, it will give you line 50, while on PHP 5.1~8.0.0 it would give you line 51:<?php$file = new SplTempFileObject();for ($i = 0; $i < 100; $i++) {    $file->fwrite("Foo $i\n");}$file->seek(50);echo json_encode(array(    array('line' => $file->key(), 'contents' => trim($file->fgets())),    array('line' => $file->key(), 'contents' => trim($file->fgets())),    array('line' => $file->key(), 'contents' => trim($file->fgets())),), JSON_PRETTY_PRINT);?>Results:PHP  8.0.1+[    {        "line": 50,        "contents": "Foo 50"    },    {        "line": 50,        "contents": "Foo 51"    },    {        "line": 51,        "contents": "Foo 52"    }]PHP 5.1 to 8.0.0[    {        "line": 50,        "contents": "Foo 51"    },    {        "line": 51,        "contents": "Foo 52"    },    {        "line": 52,        "contents": "Foo 53"    }]

Note that this method will cause a PHP fatal error if the file being read contains no recognizable line termination characters and is larger than the allowable memory size for PHP to allocate, i.e. memory_limit set in php.ini or similar.  In other words, PHP keeps reading until it finds a line termination, if it runs out of memory first, it will throw a fatal error.This is different from the file resource fread() function, which allows an optional maximum length argument to be passed to limit this behavior.

I forgot to mention in my previous note about PHP PHP 8.0.10, that you can use $file->current(); $file->next(); as a replacement for $file->fgets(); that works consistently from PHP 5.1 to 8.0.1+ after a seek():<?php$file = new SplTempFileObject();for ($i = 0; $i < 100; $i++) {    $file->fwrite("Foo $i\n");}$file->seek(50);print_r(array(    array('line' => $file->key(), 'contents' => trim($file->current()), 'triggerNext' => $file->next()),    array('line' => $file->key(), 'contents' => trim($file->current()), 'triggerNext' => $file->next()),    array('line' => $file->key(), 'contents' => trim($file->current()), 'triggerNext' => $file->next()),));?>PHP 5.1 to 8.0.1+:[    {        "line": 50,        "contents": "Foo 50"    },    {        "line": 51,        "contents": "Foo 51"    },    {        "line": 52,        "contents": "Foo 52"    }]