including SMIME_write_CMS(), i2d_CMS_bio_stream(), PEM_write_bio_CMS_stream() finalize the structure. Alternatively finalization can be performed by obtaining the streaming ASN1 <b>BIO</b> directly using BIO_new_CMS().</p>

<p>Additional compression parameters such as the zlib compression level cannot currently be set.</p>

<h1 id="RETURN-VALUES">RETURN VALUES</h1>

<p>CMS_compress() returns either a CMS_ContentInfo structure or NULL if an error occurred. The error can be obtained from ERR_get_error(3).</p>