+=head1 RETURN VALUES
+
+ASN1_TIME_set(), ASN1_UTCTIME_set(), ASN1_GENERALIZEDTIME_set(),
+ASN1_TIME_adj(), ASN1_UTCTIME_adj() and ASN1_GENERALIZEDTIME_set() return
+a pointer to a time structure or NULL if an error occurred.
+
+ASN1_TIME_set_string(), ASN1_UTCTIME_set_string(),
+ASN1_GENERALIZEDTIME_set_string() and ASN1_TIME_set_string_X509() return
+1 if the time value is successfully set and 0 otherwise.
+
+ASN1_TIME_normalize() returns 1 on success, and 0 on error.
+
+ASN1_TIME_check(), ASN1_UTCTIME_check and ASN1_GENERALIZEDTIME_check() return 1
+if the structure is syntactically correct and 0 otherwise.
+
+ASN1_TIME_print(), ASN1_UTCTIME_print() and ASN1_GENERALIZEDTIME_print() return
+1 if the time is successfully printed out and 0 if an error occurred (I/O error
+or invalid time format).
+
+ASN1_TIME_to_tm() returns 1 if the time is successfully parsed and 0 if an
+error occurred (invalid time format).
+
+ASN1_TIME_diff() returns 1 for success and 0 for failure. It can fail if the
+passed-in time structure has invalid syntax, for example.
+
+ASN1_TIME_cmp_time_t() and ASN1_UTCTIME_cmp_time_t() return -1 if I<s> is
+before I<t>, 0 if I<s> equals I<t>, or 1 if I<s> is after I<t>. -2 is returned
+on error.
+
+ASN1_TIME_compare() returns -1 if I<a> is before I<b>, 0 if I<a> equals I<b>,
+or 1 if I<a> is after I<b>. -2 is returned on error.
+
+ASN1_TIME_to_generalizedtime() returns a pointer to the appropriate time
+structure on success or NULL if an error occurred.
+
+ASN1_TIME_dup(), ASN1_UTCTIME_dup() and ASN1_GENERALIZEDTIME_dup() return a
+pointer to a time structure or NULL if an error occurred.
+