I've got an image upload script which was previously working. It's now broken, and I've traced the problem down to one line:
$temp = tmpfile();
// $temp === false
The tmpfile() function is returning false. I can't seem to figure out why. I'm having a hard time wading through Google on this one.
The script it only broken on my local test environment, OSX 10.6.7, running MAMP 1.9.5. Fortunately the live site is working fine.
tmpfile() returns false if it is unable to create the temporary file. Make sure your tmp folder is writable and try and check what sys_get_temp_dir() function returns.
It might be a problem with permissions.
Use sys_get_temp_dir() to see where the temp file will be created and make sure php has access to write there.
First, enable all PHP warnings to see if it is telling you something.
Second, check your temp folder and make sure PHP has write access to it. It's possible that certain "safe mode" restrictions (base dirs, etc) are preventing access.
In my case, the folder it was trying to create the file in had temp files ranging all the way up to tmpFFFF.tmp. After moving those temp files away from the folder, it started back at tmp1.tmp.
来源：https://stackoverflow.com/questions/6267807/php-tmpfile-returns-false