php fwrite writes the file successfully but the file has no content

I found a very strange problem. When I used fwrite to write a file, the program did not report an error. fwrite also returned the number of words written, but the content in the file was empty.

<code>        $path = Yii::$app->basePath."/upload/tt.txt";
        $file = fopen($path,'w');
        fwrite($file,'aaaaa');
        fclose($file);</code>

Using the Yii2.0 framework.
Try using file_put_contents again, but still no response O__O "…

Reply content:

I found a very strange problem. When I used fwrite to write a file, the program did not report an error. fwrite also returned the number of words written, but the content in the file was empty.

<code>        $path = Yii::$app->basePath."/upload/tt.txt";
        $file = fopen($path,'w');
        fwrite($file,'aaaaa');
        fclose($file);</code>

Using the Yii2.0 framework.
Try using file_put_contents again, but still no response O__O "…

Please check if the file has writable permissions

It feels like the writing was successful, please look for possible paths.

<code>is_writable($file) 
</code>

Determine write permission

But the author seems to have the wrong path

It should be that the path is written wrong. You can print out $path and have a look

Raise the error level of php and debug it

Please check whether the file encoding format conflicts.

Enter $path and confirm whether the path is correct