PHP error: Cannot send session cookie – headers already sent by solution

UTF-8 EF BB BF
UTF-16 Big Endian FE FF
UTF-16 Little Endian FF FE
UTF-32 Big Endian 00 00 FE FF
UTF-32 Little Endian FF FE 00 00

Solution: When performing PHP session operations, if: Warning: Cannot send session cookie – headers already sent…” or “Cannot add header information – headers already sent…” appears

Just set the Output_buffering in php.ini, the default value is no, change it to 1.