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. 成功回傳TRUE失敗回傳FALSE。 The optional notext affects the verbosity of the
output; if it is FALSE then
additional human-readable information is included in the
output. The default value of
notext is TRUE
See also openssl_csr_export(),
openssl_csr_new() and
openssl_csr_sign().