Once all signer certificates have been set CMS_verify() can be used.
-Although CMS_get0_SignerInfos() can return NULL is an error occur B<or> if
+Although CMS_get0_SignerInfos() can return NULL if an error occurs B<or> if
there are no signers this is not a problem in practice because the only
error which can occur is if the B<cms> structure is not of type signedData
due to application error.
CMS_ReceiptRequest_create0() returns a signed receipt request structure or
NULL if an error occurred.
-CMS_add1_ReceiptRequest() returns 1 for success or 0 is an error occurred.
+CMS_add1_ReceiptRequest() returns 1 for success or 0 if an error occurred.
CMS_get1_ReceiptRequest() returns 1 is a signed receipt request is found and
decoded. It returns 0 if a signed receipt request is not present and -1 if
OBJ_nid2obj(), OBJ_nid2ln() and OBJ_nid2sn() convert the NID B<n> to
an ASN1_OBJECT structure, its long name and its short name respectively,
-or B<NULL> is an error occurred.
+or B<NULL> if an error occurred.
OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() return the corresponding NID
for the object B<o>, the long name <ln> or the short name <sn> respectively
=head1 RETURN VALUES
SMIME_read_PKCS7() returns a valid B<PKCS7> structure or B<NULL>
-is an error occurred. The error can be obtained from ERR_get_error(3).
+if an error occurred. The error can be obtained from ERR_get_error(3).
=head1 SEE ALSO