1
by Tim Gardner, Andy Whitcroft, Tim Gardner
[ Andy Whitcroft ] |
1 |
Real Time Clock (RTC) Drivers for Linux |
2 |
======================================= |
|
3 |
||
4 |
When Linux developers talk about a "Real Time Clock", they usually mean |
|
5 |
something that tracks wall clock time and is battery backed so that it |
|
6 |
works even with system power off. Such clocks will normally not track |
|
7 |
the local time zone or daylight savings time -- unless they dual boot |
|
8 |
with MS-Windows -- but will instead be set to Coordinated Universal Time |
|
9 |
(UTC, formerly "Greenwich Mean Time"). |
|
10 |
||
11 |
The newest non-PC hardware tends to just count seconds, like the time(2) |
|
12 |
system call reports, but RTCs also very commonly represent time using |
|
13 |
the Gregorian calendar and 24 hour time, as reported by gmtime(3). |
|
14 |
||
15 |
Linux has two largely-compatible userspace RTC API families you may |
|
16 |
need to know about: |
|
17 |
||
18 |
* /dev/rtc ... is the RTC provided by PC compatible systems, |
|
19 |
so it's not very portable to non-x86 systems. |
|
20 |
||
21 |
* /dev/rtc0, /dev/rtc1 ... are part of a framework that's |
|
22 |
supported by a wide variety of RTC chips on all systems. |
|
23 |
||
24 |
Programmers need to understand that the PC/AT functionality is not |
|
25 |
always available, and some systems can do much more. That is, the |
|
26 |
RTCs use the same API to make requests in both RTC frameworks (using |
|
27 |
different filenames of course), but the hardware may not offer the |
|
28 |
same functionality. For example, not every RTC is hooked up to an |
|
29 |
IRQ, so they can't all issue alarms; and where standard PC RTCs can |
|
30 |
only issue an alarm up to 24 hours in the future, other hardware may |
|
31 |
be able to schedule one any time in the upcoming century. |
|
32 |
||
33 |
||
34 |
Old PC/AT-Compatible driver: /dev/rtc |
|
35 |
-------------------------------------- |
|
36 |
||
37 |
All PCs (even Alpha machines) have a Real Time Clock built into them. |
|
38 |
Usually they are built into the chipset of the computer, but some may |
|
39 |
actually have a Motorola MC146818 (or clone) on the board. This is the |
|
40 |
clock that keeps the date and time while your computer is turned off. |
|
41 |
||
42 |
ACPI has standardized that MC146818 functionality, and extended it in |
|
43 |
a few ways (enabling longer alarm periods, and wake-from-hibernate). |
|
44 |
That functionality is NOT exposed in the old driver. |
|
45 |
||
46 |
However it can also be used to generate signals from a slow 2Hz to a |
|
47 |
relatively fast 8192Hz, in increments of powers of two. These signals |
|
48 |
are reported by interrupt number 8. (Oh! So *that* is what IRQ 8 is |
|
49 |
for...) It can also function as a 24hr alarm, raising IRQ 8 when the |
|
50 |
alarm goes off. The alarm can also be programmed to only check any |
|
51 |
subset of the three programmable values, meaning that it could be set to |
|
52 |
ring on the 30th second of the 30th minute of every hour, for example. |
|
53 |
The clock can also be set to generate an interrupt upon every clock |
|
54 |
update, thus generating a 1Hz signal. |
|
55 |
||
56 |
The interrupts are reported via /dev/rtc (major 10, minor 135, read only |
|
57 |
character device) in the form of an unsigned long. The low byte contains |
|
58 |
the type of interrupt (update-done, alarm-rang, or periodic) that was |
|
59 |
raised, and the remaining bytes contain the number of interrupts since |
|
60 |
the last read. Status information is reported through the pseudo-file |
|
61 |
/proc/driver/rtc if the /proc filesystem was enabled. The driver has |
|
62 |
built in locking so that only one process is allowed to have the /dev/rtc |
|
63 |
interface open at a time. |
|
64 |
||
65 |
A user process can monitor these interrupts by doing a read(2) or a |
|
66 |
select(2) on /dev/rtc -- either will block/stop the user process until |
|
67 |
the next interrupt is received. This is useful for things like |
|
68 |
reasonably high frequency data acquisition where one doesn't want to |
|
69 |
burn up 100% CPU by polling gettimeofday etc. etc. |
|
70 |
||
71 |
At high frequencies, or under high loads, the user process should check |
|
72 |
the number of interrupts received since the last read to determine if |
|
73 |
there has been any interrupt "pileup" so to speak. Just for reference, a |
|
74 |
typical 486-33 running a tight read loop on /dev/rtc will start to suffer |
|
75 |
occasional interrupt pileup (i.e. > 1 IRQ event since last read) for |
|
76 |
frequencies above 1024Hz. So you really should check the high bytes |
|
77 |
of the value you read, especially at frequencies above that of the |
|
78 |
normal timer interrupt, which is 100Hz. |
|
79 |
||
80 |
Programming and/or enabling interrupt frequencies greater than 64Hz is |
|
81 |
only allowed by root. This is perhaps a bit conservative, but we don't want |
|
82 |
an evil user generating lots of IRQs on a slow 386sx-16, where it might have |
|
83 |
a negative impact on performance. This 64Hz limit can be changed by writing |
|
84 |
a different value to /proc/sys/dev/rtc/max-user-freq. Note that the |
|
85 |
interrupt handler is only a few lines of code to minimize any possibility |
|
86 |
of this effect. |
|
87 |
||
88 |
Also, if the kernel time is synchronized with an external source, the |
|
89 |
kernel will write the time back to the CMOS clock every 11 minutes. In |
|
90 |
the process of doing this, the kernel briefly turns off RTC periodic |
|
91 |
interrupts, so be aware of this if you are doing serious work. If you |
|
92 |
don't synchronize the kernel time with an external source (via ntp or |
|
93 |
whatever) then the kernel will keep its hands off the RTC, allowing you |
|
94 |
exclusive access to the device for your applications. |
|
95 |
||
96 |
The alarm and/or interrupt frequency are programmed into the RTC via |
|
97 |
various ioctl(2) calls as listed in ./include/linux/rtc.h |
|
98 |
Rather than write 50 pages describing the ioctl() and so on, it is |
|
99 |
perhaps more useful to include a small test program that demonstrates |
|
100 |
how to use them, and demonstrates the features of the driver. This is |
|
101 |
probably a lot more useful to people interested in writing applications |
|
102 |
that will be using this driver. See the code at the end of this document. |
|
103 |
||
104 |
(The original /dev/rtc driver was written by Paul Gortmaker.) |
|
105 |
||
106 |
||
107 |
New portable "RTC Class" drivers: /dev/rtcN |
|
108 |
-------------------------------------------- |
|
109 |
||
110 |
Because Linux supports many non-ACPI and non-PC platforms, some of which |
|
111 |
have more than one RTC style clock, it needed a more portable solution |
|
112 |
than expecting a single battery-backed MC146818 clone on every system. |
|
113 |
Accordingly, a new "RTC Class" framework has been defined. It offers |
|
114 |
three different userspace interfaces: |
|
115 |
||
116 |
* /dev/rtcN ... much the same as the older /dev/rtc interface |
|
117 |
||
118 |
* /sys/class/rtc/rtcN ... sysfs attributes support readonly |
|
119 |
access to some RTC attributes. |
|
120 |
||
121 |
* /proc/driver/rtc ... the first RTC (rtc0) may expose itself |
|
122 |
using a procfs interface. More information is (currently) shown |
|
123 |
here than through sysfs. |
|
124 |
||
125 |
The RTC Class framework supports a wide variety of RTCs, ranging from those |
|
126 |
integrated into embeddable system-on-chip (SOC) processors to discrete chips |
|
127 |
using I2C, SPI, or some other bus to communicate with the host CPU. There's |
|
128 |
even support for PC-style RTCs ... including the features exposed on newer PCs |
|
129 |
through ACPI. |
|
130 |
||
131 |
The new framework also removes the "one RTC per system" restriction. For |
|
132 |
example, maybe the low-power battery-backed RTC is a discrete I2C chip, but |
|
133 |
a high functionality RTC is integrated into the SOC. That system might read |
|
134 |
the system clock from the discrete RTC, but use the integrated one for all |
|
135 |
other tasks, because of its greater functionality. |
|
136 |
||
137 |
SYSFS INTERFACE |
|
20
by Andy Whitcroft, Eric Miao, Upstream changes
[ Eric Miao ] |
138 |
--------------- |
139 |
||
140 |
The sysfs interface under /sys/class/rtc/rtcN provides access to various |
|
141 |
rtc attributes without requiring the use of ioctls. All dates and times |
|
142 |
are in the RTC's timezone, rather than in system time. |
|
143 |
||
144 |
date: RTC-provided date |
|
145 |
hctosys: 1 if the RTC provided the system time at boot via the |
|
146 |
CONFIG_RTC_HCTOSYS kernel option, 0 otherwise |
|
147 |
max_user_freq: The maximum interrupt rate an unprivileged user may request |
|
148 |
from this RTC. |
|
149 |
name: The name of the RTC corresponding to this sysfs directory |
|
150 |
since_epoch: The number of seconds since the epoch according to the RTC |
|
151 |
time: RTC-provided time |
|
152 |
wakealarm: The time at which the clock will generate a system wakeup |
|
153 |
event. This is a one shot wakeup event, so must be reset |
|
154 |
after wake if a daily wakeup is required. Format is either |
|
155 |
seconds since the epoch or, if there's a leading +, seconds |
|
156 |
in the future. |
|
157 |
||
158 |
IOCTL INTERFACE |
|
159 |
--------------- |
|
160 |
||
161 |
The ioctl() calls supported by /dev/rtc are also supported by the RTC class |
|
1
by Tim Gardner, Andy Whitcroft, Tim Gardner
[ Andy Whitcroft ] |
162 |
framework. However, because the chips and systems are not standardized, |
163 |
some PC/AT functionality might not be provided. And in the same way, some |
|
164 |
newer features -- including those enabled by ACPI -- are exposed by the |
|
165 |
RTC class framework, but can't be supported by the older driver. |
|
166 |
||
167 |
* RTC_RD_TIME, RTC_SET_TIME ... every RTC supports at least reading |
|
168 |
time, returning the result as a Gregorian calendar date and 24 hour |
|
169 |
wall clock time. To be most useful, this time may also be updated. |
|
170 |
||
171 |
* RTC_AIE_ON, RTC_AIE_OFF, RTC_ALM_SET, RTC_ALM_READ ... when the RTC |
|
172 |
is connected to an IRQ line, it can often issue an alarm IRQ up to |
|
173 |
24 hours in the future. (Use RTC_WKALM_* by preference.) |
|
174 |
||
175 |
* RTC_WKALM_SET, RTC_WKALM_RD ... RTCs that can issue alarms beyond |
|
176 |
the next 24 hours use a slightly more powerful API, which supports |
|
177 |
setting the longer alarm time and enabling its IRQ using a single |
|
178 |
request (using the same model as EFI firmware). |
|
179 |
||
180 |
* RTC_UIE_ON, RTC_UIE_OFF ... if the RTC offers IRQs, it probably |
|
181 |
also offers update IRQs whenever the "seconds" counter changes. |
|
182 |
If needed, the RTC framework can emulate this mechanism. |
|
183 |
||
184 |
* RTC_PIE_ON, RTC_PIE_OFF, RTC_IRQP_SET, RTC_IRQP_READ ... another |
|
185 |
feature often accessible with an IRQ line is a periodic IRQ, issued |
|
186 |
at settable frequencies (usually 2^N Hz). |
|
187 |
||
188 |
In many cases, the RTC alarm can be a system wake event, used to force |
|
189 |
Linux out of a low power sleep state (or hibernation) back to a fully |
|
190 |
operational state. For example, a system could enter a deep power saving |
|
191 |
state until it's time to execute some scheduled tasks. |
|
192 |
||
193 |
Note that many of these ioctls need not actually be implemented by your |
|
194 |
driver. The common rtc-dev interface handles many of these nicely if your |
|
195 |
driver returns ENOIOCTLCMD. Some common examples: |
|
196 |
||
197 |
* RTC_RD_TIME, RTC_SET_TIME: the read_time/set_time functions will be |
|
198 |
called with appropriate values. |
|
199 |
||
200 |
* RTC_ALM_SET, RTC_ALM_READ, RTC_WKALM_SET, RTC_WKALM_RD: the |
|
201 |
set_alarm/read_alarm functions will be called. |
|
202 |
||
203 |
* RTC_IRQP_SET, RTC_IRQP_READ: the irq_set_freq function will be called |
|
204 |
to set the frequency while the framework will handle the read for you |
|
205 |
since the frequency is stored in the irq_freq member of the rtc_device |
|
206 |
structure. Your driver needs to initialize the irq_freq member during |
|
207 |
init. Make sure you check the requested frequency is in range of your |
|
208 |
hardware in the irq_set_freq function. If it isn't, return -EINVAL. If |
|
209 |
you cannot actually change the frequency, do not define irq_set_freq. |
|
210 |
||
211 |
* RTC_PIE_ON, RTC_PIE_OFF: the irq_set_state function will be called. |
|
20
by Andy Whitcroft, Eric Miao, Upstream changes
[ Eric Miao ] |
212 |
|
213 |
If all else fails, check out the rtc-test.c driver! |
|
1
by Tim Gardner, Andy Whitcroft, Tim Gardner
[ Andy Whitcroft ] |
214 |
|
215 |
||
216 |
-------------------- 8< ---------------- 8< ----------------------------- |
|
217 |
||
218 |
/* |
|
219 |
* Real Time Clock Driver Test/Example Program |
|
220 |
* |
|
221 |
* Compile with: |
|
222 |
* gcc -s -Wall -Wstrict-prototypes rtctest.c -o rtctest |
|
223 |
* |
|
224 |
* Copyright (C) 1996, Paul Gortmaker. |
|
225 |
* |
|
226 |
* Released under the GNU General Public License, version 2, |
|
227 |
* included herein by reference. |
|
228 |
* |
|
229 |
*/ |
|
230 |
||
231 |
#include <stdio.h> |
|
232 |
#include <linux/rtc.h> |
|
233 |
#include <sys/ioctl.h> |
|
234 |
#include <sys/time.h> |
|
235 |
#include <sys/types.h> |
|
236 |
#include <fcntl.h> |
|
237 |
#include <unistd.h> |
|
238 |
#include <stdlib.h> |
|
239 |
#include <errno.h> |
|
240 |
||
241 |
||
242 |
/* |
|
243 |
* This expects the new RTC class driver framework, working with |
|
244 |
* clocks that will often not be clones of what the PC-AT had. |
|
245 |
* Use the command line to specify another RTC if you need one. |
|
246 |
*/ |
|
247 |
static const char default_rtc[] = "/dev/rtc0"; |
|
248 |
||
249 |
||
250 |
int main(int argc, char **argv) |
|
251 |
{ |
|
252 |
int i, fd, retval, irqcount = 0; |
|
253 |
unsigned long tmp, data; |
|
254 |
struct rtc_time rtc_tm; |
|
255 |
const char *rtc = default_rtc; |
|
256 |
||
257 |
switch (argc) { |
|
258 |
case 2: |
|
259 |
rtc = argv[1]; |
|
260 |
/* FALLTHROUGH */ |
|
261 |
case 1: |
|
262 |
break; |
|
263 |
default: |
|
264 |
fprintf(stderr, "usage: rtctest [rtcdev]\n"); |
|
265 |
return 1; |
|
266 |
} |
|
267 |
||
268 |
fd = open(rtc, O_RDONLY); |
|
269 |
||
270 |
if (fd == -1) { |
|
271 |
perror(rtc); |
|
272 |
exit(errno); |
|
273 |
} |
|
274 |
||
275 |
fprintf(stderr, "\n\t\t\tRTC Driver Test Example.\n\n"); |
|
276 |
||
277 |
/* Turn on update interrupts (one per second) */ |
|
278 |
retval = ioctl(fd, RTC_UIE_ON, 0); |
|
279 |
if (retval == -1) { |
|
280 |
if (errno == ENOTTY) { |
|
281 |
fprintf(stderr, |
|
282 |
"\n...Update IRQs not supported.\n"); |
|
283 |
goto test_READ; |
|
284 |
} |
|
285 |
perror("RTC_UIE_ON ioctl"); |
|
286 |
exit(errno); |
|
287 |
} |
|
288 |
||
289 |
fprintf(stderr, "Counting 5 update (1/sec) interrupts from reading %s:", |
|
290 |
rtc); |
|
291 |
fflush(stderr); |
|
292 |
for (i=1; i<6; i++) { |
|
293 |
/* This read will block */ |
|
294 |
retval = read(fd, &data, sizeof(unsigned long)); |
|
295 |
if (retval == -1) { |
|
296 |
perror("read"); |
|
297 |
exit(errno); |
|
298 |
} |
|
299 |
fprintf(stderr, " %d",i); |
|
300 |
fflush(stderr); |
|
301 |
irqcount++; |
|
302 |
} |
|
303 |
||
304 |
fprintf(stderr, "\nAgain, from using select(2) on /dev/rtc:"); |
|
305 |
fflush(stderr); |
|
306 |
for (i=1; i<6; i++) { |
|
307 |
struct timeval tv = {5, 0}; /* 5 second timeout on select */ |
|
308 |
fd_set readfds; |
|
309 |
||
310 |
FD_ZERO(&readfds); |
|
311 |
FD_SET(fd, &readfds); |
|
312 |
/* The select will wait until an RTC interrupt happens. */ |
|
313 |
retval = select(fd+1, &readfds, NULL, NULL, &tv); |
|
314 |
if (retval == -1) { |
|
315 |
perror("select"); |
|
316 |
exit(errno); |
|
317 |
} |
|
318 |
/* This read won't block unlike the select-less case above. */ |
|
319 |
retval = read(fd, &data, sizeof(unsigned long)); |
|
320 |
if (retval == -1) { |
|
321 |
perror("read"); |
|
322 |
exit(errno); |
|
323 |
} |
|
324 |
fprintf(stderr, " %d",i); |
|
325 |
fflush(stderr); |
|
326 |
irqcount++; |
|
327 |
} |
|
328 |
||
329 |
/* Turn off update interrupts */ |
|
330 |
retval = ioctl(fd, RTC_UIE_OFF, 0); |
|
331 |
if (retval == -1) { |
|
332 |
perror("RTC_UIE_OFF ioctl"); |
|
333 |
exit(errno); |
|
334 |
} |
|
335 |
||
336 |
test_READ: |
|
337 |
/* Read the RTC time/date */ |
|
338 |
retval = ioctl(fd, RTC_RD_TIME, &rtc_tm); |
|
339 |
if (retval == -1) { |
|
340 |
perror("RTC_RD_TIME ioctl"); |
|
341 |
exit(errno); |
|
342 |
} |
|
343 |
||
344 |
fprintf(stderr, "\n\nCurrent RTC date/time is %d-%d-%d, %02d:%02d:%02d.\n", |
|
345 |
rtc_tm.tm_mday, rtc_tm.tm_mon + 1, rtc_tm.tm_year + 1900, |
|
346 |
rtc_tm.tm_hour, rtc_tm.tm_min, rtc_tm.tm_sec); |
|
347 |
||
348 |
/* Set the alarm to 5 sec in the future, and check for rollover */ |
|
349 |
rtc_tm.tm_sec += 5; |
|
350 |
if (rtc_tm.tm_sec >= 60) { |
|
351 |
rtc_tm.tm_sec %= 60; |
|
352 |
rtc_tm.tm_min++; |
|
353 |
} |
|
354 |
if (rtc_tm.tm_min == 60) { |
|
355 |
rtc_tm.tm_min = 0; |
|
356 |
rtc_tm.tm_hour++; |
|
357 |
} |
|
358 |
if (rtc_tm.tm_hour == 24) |
|
359 |
rtc_tm.tm_hour = 0; |
|
360 |
||
361 |
retval = ioctl(fd, RTC_ALM_SET, &rtc_tm); |
|
362 |
if (retval == -1) { |
|
363 |
if (errno == ENOTTY) { |
|
364 |
fprintf(stderr, |
|
365 |
"\n...Alarm IRQs not supported.\n"); |
|
366 |
goto test_PIE; |
|
367 |
} |
|
368 |
perror("RTC_ALM_SET ioctl"); |
|
369 |
exit(errno); |
|
370 |
} |
|
371 |
||
372 |
/* Read the current alarm settings */ |
|
373 |
retval = ioctl(fd, RTC_ALM_READ, &rtc_tm); |
|
374 |
if (retval == -1) { |
|
375 |
perror("RTC_ALM_READ ioctl"); |
|
376 |
exit(errno); |
|
377 |
} |
|
378 |
||
379 |
fprintf(stderr, "Alarm time now set to %02d:%02d:%02d.\n", |
|
380 |
rtc_tm.tm_hour, rtc_tm.tm_min, rtc_tm.tm_sec); |
|
381 |
||
382 |
/* Enable alarm interrupts */ |
|
383 |
retval = ioctl(fd, RTC_AIE_ON, 0); |
|
384 |
if (retval == -1) { |
|
385 |
perror("RTC_AIE_ON ioctl"); |
|
386 |
exit(errno); |
|
387 |
} |
|
388 |
||
389 |
fprintf(stderr, "Waiting 5 seconds for alarm..."); |
|
390 |
fflush(stderr); |
|
391 |
/* This blocks until the alarm ring causes an interrupt */ |
|
392 |
retval = read(fd, &data, sizeof(unsigned long)); |
|
393 |
if (retval == -1) { |
|
394 |
perror("read"); |
|
395 |
exit(errno); |
|
396 |
} |
|
397 |
irqcount++; |
|
398 |
fprintf(stderr, " okay. Alarm rang.\n"); |
|
399 |
||
400 |
/* Disable alarm interrupts */ |
|
401 |
retval = ioctl(fd, RTC_AIE_OFF, 0); |
|
402 |
if (retval == -1) { |
|
403 |
perror("RTC_AIE_OFF ioctl"); |
|
404 |
exit(errno); |
|
405 |
} |
|
406 |
||
407 |
test_PIE: |
|
408 |
/* Read periodic IRQ rate */ |
|
409 |
retval = ioctl(fd, RTC_IRQP_READ, &tmp); |
|
410 |
if (retval == -1) { |
|
411 |
/* not all RTCs support periodic IRQs */ |
|
412 |
if (errno == ENOTTY) { |
|
413 |
fprintf(stderr, "\nNo periodic IRQ support\n"); |
|
414 |
goto done; |
|
415 |
} |
|
416 |
perror("RTC_IRQP_READ ioctl"); |
|
417 |
exit(errno); |
|
418 |
} |
|
419 |
fprintf(stderr, "\nPeriodic IRQ rate is %ldHz.\n", tmp); |
|
420 |
||
421 |
fprintf(stderr, "Counting 20 interrupts at:"); |
|
422 |
fflush(stderr); |
|
423 |
||
424 |
/* The frequencies 128Hz, 256Hz, ... 8192Hz are only allowed for root. */ |
|
425 |
for (tmp=2; tmp<=64; tmp*=2) { |
|
426 |
||
427 |
retval = ioctl(fd, RTC_IRQP_SET, tmp); |
|
428 |
if (retval == -1) { |
|
429 |
/* not all RTCs can change their periodic IRQ rate */ |
|
430 |
if (errno == ENOTTY) { |
|
431 |
fprintf(stderr, |
|
432 |
"\n...Periodic IRQ rate is fixed\n"); |
|
433 |
goto done; |
|
434 |
} |
|
435 |
perror("RTC_IRQP_SET ioctl"); |
|
436 |
exit(errno); |
|
437 |
} |
|
438 |
||
439 |
fprintf(stderr, "\n%ldHz:\t", tmp); |
|
440 |
fflush(stderr); |
|
441 |
||
442 |
/* Enable periodic interrupts */ |
|
443 |
retval = ioctl(fd, RTC_PIE_ON, 0); |
|
444 |
if (retval == -1) { |
|
445 |
perror("RTC_PIE_ON ioctl"); |
|
446 |
exit(errno); |
|
447 |
} |
|
448 |
||
449 |
for (i=1; i<21; i++) { |
|
450 |
/* This blocks */ |
|
451 |
retval = read(fd, &data, sizeof(unsigned long)); |
|
452 |
if (retval == -1) { |
|
453 |
perror("read"); |
|
454 |
exit(errno); |
|
455 |
} |
|
456 |
fprintf(stderr, " %d",i); |
|
457 |
fflush(stderr); |
|
458 |
irqcount++; |
|
459 |
} |
|
460 |
||
461 |
/* Disable periodic interrupts */ |
|
462 |
retval = ioctl(fd, RTC_PIE_OFF, 0); |
|
463 |
if (retval == -1) { |
|
464 |
perror("RTC_PIE_OFF ioctl"); |
|
465 |
exit(errno); |
|
466 |
} |
|
467 |
} |
|
468 |
||
469 |
done: |
|
470 |
fprintf(stderr, "\n\n\t\t\t *** Test complete ***\n"); |
|
471 |
||
472 |
close(fd); |
|
473 |
||
474 |
return 0; |
|
475 |
} |
|
476 |