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I was playing around with a small piece of code that queries port 37 on host 129.6.15.28 to get the date and time. It consistently gives me back 3435973836. Doing the conversion, that's roughly 108.8 years after January 1, 1900 (the epoch). For today, I would have expected a number close to 3461794781. Questions: 1) why would I keep getting the same number, and 2) why is it not the right number?
SOCKET rSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
unsigned long ul = 1;
ioctlsocket(rSocket, FIONBIO, &ul);
SOCKADDR_IN rSocketAddr;
rSocketAddr.sin_family = AF_INET;
rSocketAddr.sin_addr.s_addr = inet_addr("129.6.15.28");
rSocketAddr.sin_port = htons(37);
connect(rSocket, (LPSOCKADDR) &rSocketAddr, sizeof(rSocketAddr));
unsigned int nData = 0;
recv(rSocket, (char *) &nData, sizeof(nData), 0);
TRACE("%u\n", nData);Update: initializing nData to 0 answers the questions as to why recv() was consistently assigning 3435973836 to nData. After a few more rounds of testing, the culprit looks to be the call to ioctlsocket() which made the socket non-blocking.
"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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Uhm....Have you seen the hex representation of the number 3435973836 (0xCCCCCCCC)?
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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Yes. I realize it's likely a special value, but without knowing what, it's currently just another number.
"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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I suppose the address of operator will remove the special value.
recv(rSocket, &nData, sizeof(nData), 0);
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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My bad. What I had would have actually resulted in a compiler error (which I obviously don't have).
"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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Hey David, if my understanding is correct, you keep receiving 0xCCCCCCCC. If it is so, you probably are plainly receiving nothing and should check recv return value.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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I am checking the return value, I just didn't bother putting in my code snippet. It's always 4.
"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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Should
recv(rSocket, nData, sizeof(nData), 0);
be
recv(rSocket, (void*)&nData, sizeof(nData), 0);
You need to give recv a pointer to put the data into...
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
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PS - you also need to convert the received data (nData) to host byte-ordering from network byte-ordering using ntohl:
unsigned int nData;
recv(rSocket, &nData, sizeof(nData), 0);
nData = ntohl(nData);
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
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No matter how you swap 0xcccccccc, it always comes out the same. 
"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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Not if you do it really fast!
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But if you implement the other fix I mentioned, you won't be getting 0xcccccccc…I didn't, anyway.
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
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I was already using a pointer. Had I not been, the code would not have even compiled.
"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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Well I knew only DavidCrow could solve your problem. 
BTW eventually I did some test (at home, since I could not reach the server at work), using:
-
unsigned long ul = 1;
unsigned long ul = 0;
ioctlsocket(rSocket, FIONBIO, &ul);
-
unsigned long ul = 1;
ioctlsocket(rSocket, FIONBIO, &ul);
-
For all cases I got reasonable values (growing numbers, starting from 3462291165). What do you think about?
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
modified on Friday, September 18, 2009 4:31 PM
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What is the difference between 1 and 2? I simply tried with and without the call to ioctlsocket(). The former failed (i.e., recv() never updated the buffer) while the latter succeeded.
"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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DavidCrow wrote: What is the difference between 1 and 2?
My bad, I fixed it. 
What puzzles me is:
- Why on my system it works in all cases?
- Why on your system, whenever it fails, you get
4 as result of recv?
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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CPallini wrote: Why on my system it works in all cases?
Other than error checking, do you have any more/less code than what I've shown?
"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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Hello
Can anyone tell me how to convert Julian date/time to Normal (standard) date/time
and back?
Any sample source code will help?
I do have some code, but the problem is, if the TIME is before 12 Noon, then it will
show the previous DAY.
i.e., if the actual time now is Sep 17th 10:30 AM
My code will give me the date as Sep 16th 10:30 AM
But if the current time is Sep 17th 10>30 PM
then it will give the exact day.
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dipuks wrote: Can anyone tell me how to convert Julian date/time to Normal (standard) date/time
and back?
What is your Julian date's epoch?
Have you seen this?
What does your date/time value look like?
"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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what is a epoch?
am very new to julian date/time
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dipuks wrote: what is a epoch?
See here.
"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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starting from 1 january 1899 to current date
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Ok the problem that i am having is with calculating the time...
i.e, if the time is BEFORE NOON, that is an hour value less than 12,
then the calculation gives a negative number.
when that is added with the DAY number, it actually goes back by a day.
It seems there's no perfect way of calculating the julian time if hour is less than 12?
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Julian dates are intervals of time in days and fractions of a day since some epoch. Again, what does your Julian date look like?
"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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i have to convert todays date into julian and then reconvert it back to normal date.
can you tell me how to do that?
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