这是关于它的说明:
It is very important to note that the line with the closing identifier contains no other characters, except possibly a semicolon (;). That means especially that the identifier may not be indented, and there may not be any spaces or tabs after or before the semicolon. Probably the nastiest gotcha is that there may also not be a carriage return (\r) at the end of the line, only a form feed, AKA newline (\n). Since Microsoft Windows uses the sequence \r\n as a line terminator, your heredoc may not work if you write your script in a Windows editor. However, most programming editors provide a way to save your files with a UNIX line terminator.
It is very important to note that the line with the closing identifier contains no other characters, except possibly a semicolon (;). That means especially that the identifier may not be indented, and there may not be any spaces or tabs after or before the semicolon. Probably the nastiest gotcha is that there may also not be a carriage return (\r) at the end of the line, only a form feed, AKA newline (\n). Since Microsoft Windows uses the sequence \r\n as a line terminator, your heredoc may not work if you write your script in a Windows editor. However, most programming editors provide a way to save your files with a UNIX line terminator.
好像是end不是eod
echo打印end与end之间的内容
这是PHP的一种字符串表示法.
以 <<<自定义单词 开头,并以同样的方式结尾.注意,结尾的单词一定要在行首.