diff --git a/src/libiso8601/.types.h.swp b/src/libiso8601/.types.h.swp
deleted file mode 100644
index 800743c..0000000
Binary files a/src/libiso8601/.types.h.swp and /dev/null differ
diff --git a/src/libiso8601/TopSource.c b/src/libiso8601/TopSource.c
index f890996..2045dbf 100644
--- a/src/libiso8601/TopSource.c
+++ b/src/libiso8601/TopSource.c
@@ -10,6 +10,10 @@
 // Below are all the includes used throughout the library.
 #include <errno.h>
 #include <stdlib.h>
+#include <string.h>
+
+
+#include <stdio.h>
 
 /* options for text editors
 kate: replace-trailing-space-save true; space-indent true; tab-width 4;
diff --git a/src/libiso8601/build.monolithic b/src/libiso8601/build.monolithic
index 4fe847c..9245773 100644
--- a/src/libiso8601/build.monolithic
+++ b/src/libiso8601/build.monolithic
@@ -11,7 +11,7 @@ then
     MONOLITHIC_SOURCE="$(echo src/libiso8601/{TopHeader,types,functions,BottomHeader}.h)"
     make_monolithic ${HDR} Ch || return 1
 
-    MONOLITHIC_SOURCE="$(echo src/libiso8601/{TopSource,c_library,calc,parser}.c)"
+    MONOLITHIC_SOURCE="$(echo src/libiso8601/{TopSource,c_library,calc,parser,print,manip}.c)"
     make_monolithic ${SRC} C || return 1
 
     libiso8601_MONOLITHIC=1
diff --git a/src/libiso8601/c_library.c b/src/libiso8601/c_library.c
index 8d2f734..0ec4e75 100644
--- a/src/libiso8601/c_library.c
+++ b/src/libiso8601/c_library.c
@@ -5,24 +5,32 @@
  *  http://www.gnu.org/copyleft/gpl.html for details.
 */
 
+// days between 0000-001 and 1970-001 (the unix epoch)
+#define EPOCH_GDAY (719528)
+
 
 
 void iso8601_now(struct iso8601_date* date, struct iso8601_details* details)
 {
     struct timespec ts;
+    struct tm tm;
+
+    clock_gettime(CLOCK_REALTIME, &ts);
 
     // populate the `struct iso8601_date' if it was passed
     if(date) {
-        clock_gettime(CLOCK_REALTIME, &ts);
         iso8601_from_ts(date, &ts);
     }
 
     // populate the `struct iso8601_details' if it was passed
     if(details) {
-        tzset();
+        memset(details, 0, sizeof(struct iso8601_details));
         details->date_prec = iso8601_prec_day;
         details->time_prec = iso8601_prec_secfrac;
-        details->tz_sec = timezone;
+
+        // this is silly, but it's the only way to recover the timezone
+        localtime_r(&ts.tv_sec, &tm);
+        details->tz_sec = tm.tm_gmtoff;
     }
 }
 
@@ -33,7 +41,7 @@ void iso8601_from_ts(struct iso8601_date* date, const struct timespec* ts)
     ldiv_t qr;
 
     qr = ldiv(ts->tv_sec, 86400);
-    date->day = /* XXX days between 0000-001 and 1970-001 */ + qr.quot;
+    date->day = EPOCH_GDAY + qr.quot;
     date->sec = qr.rem;
     date->nsec = ts->tv_nsec;
 }
@@ -42,7 +50,7 @@ void iso8601_from_ts(struct iso8601_date* date, const struct timespec* ts)
 
 void iso8601_to_ts(struct timespec* ts, const struct iso8601_date* date)
 {
-    ts->tv_sec = 86400L * date->day + date->sec;
+    ts->tv_sec = 86400L * (date->day - EPOCH_GDAY) + date->sec;
     ts->tv_nsec = date->nsec;
 }
 
@@ -53,7 +61,7 @@ void iso8601_from_time_t(struct iso8601_date* date, const time_t* t)
     ldiv_t qr;
 
     qr = ldiv(*t, 86400);
-    date->day = /* XXX days between 0000-001 and 1970-001 */ + qr.quot;
+    date->day = EPOCH_GDAY + qr.quot;
     date->sec = qr.rem;
     date->nsec = 0;
 }
@@ -62,8 +70,7 @@ void iso8601_from_time_t(struct iso8601_date* date, const time_t* t)
 
 void iso8601_to_time_t(time_t* t, const struct iso8601_date* date)
 {
-    *t = 86400L * date->day + date->sec;
-    if(date->nsec >= 500000000) ++*t;
+    *t = 86400L * (date->day - EPOCH_GDAY) + date->sec;
 }
 
 
diff --git a/src/libiso8601/functions.h b/src/libiso8601/functions.h
index 0b96c34..d03d219 100644
--- a/src/libiso8601/functions.h
+++ b/src/libiso8601/functions.h
@@ -21,6 +21,13 @@ int iso8601_isleap(int year);
 void iso8601_to_cal(int* year, int* month, int* day, const struct iso8601_date* date);
 int iso8601_from_cal(struct iso8601_date* date, int year, int month, int day);
 
+/* print.c */
+void iso8601_print(char* str, int amt, const struct iso8601_date* date, 
+    const struct iso8601_details* details);
+
+/* manip.c */
+void iso8601_add_seconds(struct iso8601_date* date, long seconds);
+
 /* options for text editors
 kate: replace-trailing-space-save true; space-indent true; tab-width 4;
 vim: expandtab:ts=4:sw=4
diff --git a/src/libiso8601/manip.c b/src/libiso8601/manip.c
new file mode 100644
index 0000000..0f162b2
--- /dev/null
+++ b/src/libiso8601/manip.c
@@ -0,0 +1,31 @@
+/* libiso8601/src/libiso8601/manip.c
+ *
+ *  (c)2006, Laurence Withers, <l@lwithers.me.uk>.
+ *  Released under the GNU GPLv2. See file COPYING or
+ *  http://www.gnu.org/copyleft/gpl.html for details.
+*/
+
+
+
+void iso8601_add_seconds(struct iso8601_date* date, long seconds)
+{
+    ldiv_t qr;
+
+    switch(date->sec) {
+    case 86400:
+    case 86401:
+        --date->sec; 
+        break;
+    }
+    
+    qr = ldiv(seconds + date->sec, 86400);
+    date->day += qr.quot;
+    date->sec = qr.rem;
+}
+
+
+
+/* options for text editors
+kate: replace-trailing-space-save true; space-indent true; tab-width 4;
+vim: expandtab:ts=4:sw=4
+*/
diff --git a/src/libiso8601/print.c b/src/libiso8601/print.c
new file mode 100644
index 0000000..d306906
--- /dev/null
+++ b/src/libiso8601/print.c
@@ -0,0 +1,154 @@
+/* libiso8601/src/libiso8601/print.c
+ *
+ *  (c)2006, Laurence Withers, <l@lwithers.me.uk>.
+ *  Released under the GNU GPLv2. See file COPYING or
+ *  http://www.gnu.org/copyleft/gpl.html for details.
+*/
+
+
+
+static const struct iso8601_details _default_details = {
+    iso8601_prec_day,
+    iso8601_prec_sec,
+    1,
+    0
+};
+
+
+
+void iso8601_print(char* str, int amt, const struct iso8601_date* date, 
+    const struct iso8601_details* details)
+{
+    int y, m, d, ret, extended;
+    struct iso8601_date dttz;
+    double frac;
+
+    // use default details if none provided
+    if(!details) details = &_default_details;
+
+    // adjust output for timezone
+    dttz = *date;
+    iso8601_add_seconds(&dttz, details->tz_sec);
+
+    // determine whether or not to force extended output
+    iso8601_to_cal(&y, &m, &d, &dttz);
+    extended = details->extended || y < 0 || y > 9999;
+
+    switch(details->date_prec) {
+    case iso8601_prec_year:
+        if(y < 0) snprintf(str, amt, "%05d", y);
+        else snprintf(str, amt, "%04d", y);
+        return;
+
+    case iso8601_prec_month:
+        iso8601_to_cal(&y, &m, &d, &dttz);
+        if(y < 0) snprintf(str, amt, "%05d-%02d", y, m);
+        else snprintf(str, amt, extended ? "%04d-%02d" : "%04d%02d", y, m);
+        return;
+
+    case iso8601_prec_day:
+        iso8601_to_cal(&y, &m, &d, &dttz);
+        if(y < 0) ret = snprintf(str, amt, "%05d-%02d-%02d", y, m, d);
+        ret = snprintf(str, amt, extended ? "%04d-%02d-%02d" : "%04d%02d%02d", y, m, d);
+        break;
+
+    default:
+        fprintf(stderr, "<<< NOT IMPLEMENTED >>>\n");
+        abort();
+    }
+
+    if(ret < 1 || ret >= amt) return;
+    str += ret;
+    amt -= ret;
+
+    switch(dttz.sec) {
+    case 86400:
+        y = 23;
+        m = 59;
+        d = 60;
+        break;
+
+    case 86401:
+        y = 24;
+        m = 0;
+        d = 0;
+        break;
+
+    default:
+        y = dttz.sec / 3600;
+        dttz.sec -= y * 3600;
+        m = dttz.sec / 60;
+        dttz.sec -= m * 60;
+        d = dttz.sec;
+    }
+
+    switch(details->time_prec) {
+    case iso8601_prec_none:
+        return;
+
+    case iso8601_prec_hour:
+        ret = snprintf(str, amt, "T%02d", y);
+        break;
+
+    case iso8601_prec_min:
+        ret = snprintf(str, amt, extended ? "T%02d:%02d" : "T%02d%02d", y, m);
+        break;
+
+    case iso8601_prec_sec:
+        ret = snprintf(str, amt, extended ? "T%02d:%02d:%02d" : "T%02d%02d%02d", y, m, d);
+        break;
+
+    case iso8601_prec_hourfrac:
+        frac = y + m / 60.0 + (d + date->nsec / 1e9) / 3600.0;
+        ret = snprintf(str, amt, "T%#09.6f", frac);
+        break;
+
+    case iso8601_prec_minfrac:
+        frac = m + (d + date->nsec / 1e9) / 60.0;
+        ret = snprintf(str, amt, extended ? "T%02d:%#09.6f" : "T%02d%#09.6f", y, frac);
+        break;
+
+    case iso8601_prec_secfrac:
+        frac = d + date->nsec / 1e9;
+        ret = snprintf(str, amt, extended ? "T%02d:%02d:%#09.6f" : "T%02d%02d%#09.6f", y, m, frac);
+        break;
+    }
+
+    if(ret < 1 || ret >= amt) return;
+    str += ret;
+    amt -= ret;
+
+    if(details->tz_sec) {
+        if(!--amt) {
+            *str = 0;
+            return;
+        }
+        if(details->tz_sec < 0) {
+            *str++ = '-';
+            ret = -details->tz_sec;
+        } else {
+            *str++ = '+';
+            ret = details->tz_sec;
+        }
+
+        y = ret / 3600;
+        ret -= y * 3600;
+        m = ret / 60;
+        ret -= m * 60;
+        d = ret;
+
+        if(d) snprintf(str, amt, extended ? "%02d:%02d:%02d" : "%02d%02d%02d", y, m, d);
+        else if(m) snprintf(str, amt, extended ? "%02d:%02d" : "%02d%02d", y, m);
+        else snprintf(str, amt, "%02d", y);
+    } else {
+        *str++ = 'Z';
+        if(amt > 1) *str = 0;
+    }
+}
+
+
+
+/* options for text editors
+kate: replace-trailing-space-save true; space-indent true; tab-width 4;
+vim: expandtab:ts=4:sw=4
+*/
diff --git a/src/libiso8601/types.h b/src/libiso8601/types.h
index 84caf21..3b80717 100644
--- a/src/libiso8601/types.h
+++ b/src/libiso8601/types.h
@@ -8,9 +8,9 @@
 
 
 struct iso8601_date {
-        uint32_t nsec;
+        int32_t nsec;
         int32_t day;
-        uint32_t sec;
+        int32_t sec; // special values: 86400 == leap second 23:59:60, 86401 == midnight 24:00:00
 };
 
 enum iso8601_date_prec {
@@ -33,7 +33,7 @@ enum iso8601_time_prec {
 }time_prec;
 
 struct iso8601_details {
-        uint8_t date_prec, time_prec;
+        uint8_t date_prec, time_prec, extended;
         int32_t tz_sec;
 };
 
diff --git a/src/tests/printer.c b/src/tests/printer.c
new file mode 100644
index 0000000..f629274
--- /dev/null
+++ b/src/tests/printer.c
@@ -0,0 +1,189 @@
+/* libiso8601/src/tests/printer.c
+ *
+ *  (c)2006, Laurence Withers, <l@lwithers.me.uk>.
+ *  Released under the GNU GPLv2. See file COPYING or
+ *  http://www.gnu.org/copyleft/gpl.html for details.
+*/
+
+#include "iso8601.h"
+
+#include <stdio.h>
+#include <string.h>
+
+
+
+void do_details_local(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+}
+
+void do_details_local_nofrac(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->time_prec = iso8601_prec_sec;
+}
+
+void do_details_local_min(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->time_prec = iso8601_prec_min;
+}
+
+void do_details_local_minfrac(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->time_prec = iso8601_prec_minfrac;
+}
+
+void do_details_local_hour(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->time_prec = iso8601_prec_hour;
+}
+
+void do_details_local_hourfrac(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->time_prec = iso8601_prec_hourfrac;
+}
+
+void do_details_local_day(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->time_prec = iso8601_prec_none;
+}
+
+void do_details_local_month(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->date_prec = iso8601_prec_month;
+}
+
+void do_details_local_year(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->date_prec = iso8601_prec_year;
+}
+
+void do_details_utc(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->tz_sec = 0;
+}
+
+void do_details_utc_nofrac(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->tz_sec = 0;
+    dt_out->time_prec = iso8601_prec_sec;
+}
+
+void do_details_utc_min(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->tz_sec = 0;
+    dt_out->time_prec = iso8601_prec_min;
+}
+
+void do_details_utc_minfrac(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->tz_sec = 0;
+    dt_out->time_prec = iso8601_prec_minfrac;
+}
+
+void do_details_utc_hour(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->tz_sec = 0;
+    dt_out->time_prec = iso8601_prec_hour;
+}
+
+void do_details_utc_hourfrac(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->tz_sec = 0;
+    dt_out->time_prec = iso8601_prec_hourfrac;
+}
+
+void do_details_utc_day(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->tz_sec = 0;
+    dt_out->time_prec = iso8601_prec_none;
+}
+
+void do_details_utc_month(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->tz_sec = 0;
+    dt_out->date_prec = iso8601_prec_month;
+}
+
+void do_details_utc_year(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->tz_sec = 0;
+    dt_out->date_prec = iso8601_prec_year;
+}
+
+
+
+struct test {
+    const char* desc;
+    void (*do_details)(struct iso8601_details* dt_out, const struct iso8601_details* dt_in);
+};
+const struct test tests[] = {
+    { "UTC with fraction", do_details_utc },
+    { "UTC without fraction", do_details_utc_nofrac },
+    { "UTC minute", do_details_utc_min },
+    { "UTC minute with fraction", do_details_utc_minfrac },
+    { "UTC hour", do_details_utc_hour },
+    { "UTC hour with fraction", do_details_utc_hourfrac },
+    { "UTC day", do_details_utc_day },
+    { "UTC month", do_details_utc_month },
+    { "UTC year", do_details_utc_year },
+    { "Local with fraction", do_details_local },
+    { "Local without fraction", do_details_local_nofrac },
+    { "Local minute", do_details_local_min },
+    { "Local minute with fraction", do_details_local_minfrac },
+    { "Local hour", do_details_local_hour },
+    { "Local hour with fraction", do_details_local_hourfrac },
+    { "Local day", do_details_local_day },
+    { "Local month", do_details_local_month },
+    { "Local year", do_details_local_year },
+    { 0, 0 }
+};
+
+
+
+int main(int argc, char* argv[])
+{
+    int ret = 0;
+    struct iso8601_date dt;
+    struct iso8601_details details, details2;
+    char buf[100], buf2[100];
+    const struct test* test;
+
+    if(argc == 2 && !strcmp(argv[1], "--print-summary")) {
+        printf("Prints the current time in various formats.\n");
+        return 0;
+    }
+
+    iso8601_now(&dt, &details);
+    printf("%-30s  %-30s  %s\n", "Name", "Basic format", "Extended format");
+    for(test = tests; test->desc; ++test) {
+        test->do_details(&details2, &details);
+        iso8601_print(buf, sizeof(buf), &dt, &details2);
+        ++details2.extended;
+        iso8601_print(buf2, sizeof(buf2), &dt, &details2);
+        printf("%-30s  %-30s  %s\n", test->desc, buf, buf2);
+    }
+
+    return ret;
+}
+
+/* options for text editors
+kate: replace-trailing-space-save true; space-indent true; tab-width 4;
+vim: expandtab:ts=4:sw=4
+*/