PHP session_start () about cannot send session cache Limiter-headers already sent error resolution _php tips

said that there is already output, with the editor to fight, clearly there is nothing in front, originally in the use of Ajax, also appeared in this situation, and later, put the PHP file into Linux Open, will find that in the first file, there will be "nobelium" such a character (quotation marks), remove it later, and then run, OK, normal operation. Later on the Internet to search for some files, the explanation is: UTF8 file BOM (Byte order mark) logo, when saved will automatically deposit!
No matter what it is, now the goal is to remove it, I summarized the following three kinds of methods:
1, under the Linux open, remove and then save
2, open with WordPad, put the cursor to the front and back, and then knock Delete, back to the first line, so that the front of the character will be removed
3, using the UltraEdit editor (very good use of an editor, the internet is more, their own down), open the Advanced----configuration----unicode/utf-8 detection, automatically detect UTF-8 files, automatic detection of no BOM, such as Unicode files, such as the front of the hook all removed, Then you open the file again, you will find the "Nobelium" this character appears, delete the OK


Stupid method: Is there a lot of pages when you do the same?
In the PHP page header directly set Ob_start (), you can solve!

Solution:
Modify Session.auto_start = 0 for session.auto_start = 1 in php.ini
output_buffering = change to On or any number.
And don't forget to reboot ...