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.
Parameters
csr
outfilename
Path to the output file.
notext
The optional parameter 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.