SMIME_write_PKCS7 - convert PKCS#7 structure to S/MIME format

SMIME_write_PKCS7() always base64 encodes PKCS#7 structures, there should be an option to disable this.

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       Licensed under the Apache License 2.0 (the "License").  You may not use this file except in compliance
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3.5.0                                              2025-06-04                            SMIME_WRITE_PKCS7(3SSL)

SMIME_write_PKCS7() adds the appropriate MIME headers to a PKCS#7 structure to produce an S/MIME message.

       out is the BIO to write the data to. p7 is the appropriate PKCS7 structure. If streaming is enabled then
       the content must be supplied in the data argument. flags is an optional set of flags.

       SMIME_write_PKCS7 - convert PKCS#7 structure to S/MIME format

       The following flags can be passed in the flags parameter.

       If PKCS7_DETACHED is set then cleartext signing will be used, this option only makes sense for signedData
       where PKCS7_DETACHED is also set when PKCS7_sign() is also called.

       If the PKCS7_TEXT flag is set MIME headers for type text/plain are added to the content, this only makes
       sense if PKCS7_DETACHED is also set.

       If the PKCS7_STREAM flag is set streaming is performed. This flag should only be set if PKCS7_STREAM was
       also set in the previous call to PKCS7_sign() or PKCS7_encrypt().

       If cleartext signing is being used and PKCS7_STREAM not set then the data must be read twice: once to
       compute the signature in PKCS7_sign() and once to output the S/MIME message.

       If streaming is performed the content is output in BER format using indefinite length constructed
       encoding except in the case of signed data with detached content where the content is absent and DER
       format is used.

SMIME_write_PKCS7() returns 1 for success or 0 for failure.

ERR_get_error(3), PKCS7_sign(3), PKCS7_verify(3), PKCS7_encrypt(3) PKCS7_decrypt(3)

        #include <openssl/pkcs7.h>

        int SMIME_write_PKCS7(BIO *out, PKCS7 *p7, BIO *data, int flags);