(PHP 4 >= 4.2.0, PHP 5, PHP 7)
openssl_csr_export_to_file — Exports a CSR to a file
$csr
   , string $outfilename
   [, bool $notext = true
  ] )
   openssl_csr_export_to_file() takes the Certificate
   Signing Request represented by csr and saves it
   as ascii-armoured text into the file named by outfilename.
  
csr
outfilenamePath to the output file.
notext
可选参数 notext 影响输出的冗余度。如果设为
FALSE,输出内容将包含附加的人类可读信息。notext 的缺省值为 TRUE。
   成功时返回 TRUE, 或者在失败时返回 FALSE。