A problem with loops
-
VonHagNDaz wrote:
number of channels represents the differnt ink cartridges inside of the E*s*n printers we are modifying. 1 - 8 for dual CMYK printing...Out is the pixel data for that channel, and OutLen is the length of the data that is expected. say 16 pixel wide image, four ink channels, you would end up with four arrays each containing the color data for that specific channel for each pixel.
That's all well and good, but it did nothing to answer my questions. When I asked about
NumberOfChannels, is it anint,short,char, etc? What value does it have (not what it should have) at the start of theforloop?
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
sorry about that, Channel is an int and is set to zero at the start of the loop, out is an unsigned char*, and Outlen is and unsigned int.
I win because I have the most fun in life...
-
sorry about that, Channel is an int and is set to zero at the start of the loop, out is an unsigned char*, and Outlen is and unsigned int.
I win because I have the most fun in life...
VonHagNDaz wrote:
Channel is an int and is set to zero at the start of the loop,
That's obvious from your code snippet. I was asking about
NumberOfChannels.VonHagNDaz wrote:
...out is an unsigned char*...
But what is its size? If it has not been initialized,
memset()should fail ifOutLenis anything other than 0 or 1.VonHagNDaz wrote:
Outlen is and unsigned int.
But what is its value at the time of
memset()?
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
-
VonHagNDaz wrote:
Channel is an int and is set to zero at the start of the loop,
That's obvious from your code snippet. I was asking about
NumberOfChannels.VonHagNDaz wrote:
...out is an unsigned char*...
But what is its size? If it has not been initialized,
memset()should fail ifOutLenis anything other than 0 or 1.VonHagNDaz wrote:
Outlen is and unsigned int.
But what is its value at the time of
memset()?
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
man, im sorry i keep making you ask me twice, i dont know where my head is at this morning. NumberOfChannels is an int. both NumberOfChannels and Outlen are set outside by the calling class, and not altered with in this class.
I win because I have the most fun in life...
-
man, im sorry i keep making you ask me twice, i dont know where my head is at this morning. NumberOfChannels is an int. both NumberOfChannels and Outlen are set outside by the calling class, and not altered with in this class.
I win because I have the most fun in life...
VonHagNDaz wrote:
NumberOfChannels is an int.
Ok, but you still have not indicated their respective values prior to being used. Can you not just set a breakpoint on the
forandmemset()statements and look at their values in the watch window?
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
-
VonHagNDaz wrote:
NumberOfChannels is an int.
Ok, but you still have not indicated their respective values prior to being used. Can you not just set a breakpoint on the
forandmemset()statements and look at their values in the watch window?
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
there values are NumberOfChannels 4 and OutLen 2692. its just randomly that Channel = -1. Sometimes everything works out and Channel never goes to -1, and it never goes to -1 at the same iteration through the loop. It crashes either randomly, or not at all.
I win because I have the most fun in life...
-
there values are NumberOfChannels 4 and OutLen 2692. its just randomly that Channel = -1. Sometimes everything works out and Channel never goes to -1, and it never goes to -1 at the same iteration through the loop. It crashes either randomly, or not at all.
I win because I have the most fun in life...
VonHagNDaz wrote:
...and OutLen 2692.
So does
Outhave enough room for 2692 characters?VonHagNDaz wrote:
its just randomly that Channel = -1.
Computers never do anything at random. They do exactly what they were instructed to do.
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
-
VonHagNDaz wrote:
...and OutLen 2692.
So does
Outhave enough room for 2692 characters?VonHagNDaz wrote:
its just randomly that Channel = -1.
Computers never do anything at random. They do exactly what they were instructed to do.
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
DavidCrow wrote:
They do exactly what they were instructed to do
You have to use the good ole fashion "tool blame" to keep a small amount of sanity. Yes, it is being allocated the proper space. A coworker has suggested that it might be a memory error where something is writing to that chunk and skewing the number?
I win because I have the most fun in life...
-
DavidCrow wrote:
They do exactly what they were instructed to do
You have to use the good ole fashion "tool blame" to keep a small amount of sanity. Yes, it is being allocated the proper space. A coworker has suggested that it might be a memory error where something is writing to that chunk and skewing the number?
I win because I have the most fun in life...
VonHagNDaz wrote:
A coworker has suggested that it might be a memory error where something is writing to that chunk and skewing the number?
That's what I've been tring to get at for several posts now, but without having any actual numbers, could not be for sure.
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
-
VonHagNDaz wrote:
A coworker has suggested that it might be a memory error where something is writing to that chunk and skewing the number?
That's what I've been tring to get at for several posts now, but without having any actual numbers, could not be for sure.
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
is there some slick way to see whats going on? ive tried watching that address with the memory view part of the debugger, but it doesnt show where anything is writing to that address.
I win because I have the most fun in life...
-
is there some slick way to see whats going on? ive tried watching that address with the memory view part of the debugger, but it doesnt show where anything is writing to that address.
I win because I have the most fun in life...
Set a breakpoint on any of the statements within the
forloop. AddChannelto the watch window. Go through theforloop using F5. WatchChannelat each iteration. Hopefully you'll see it change to -1.
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
-
Set a breakpoint on any of the statements within the
forloop. AddChannelto the watch window. Go through theforloop using F5. WatchChannelat each iteration. Hopefully you'll see it change to -1.
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
I appreciate the help, and im glad you havent just gotten fed up with me, but this loop is called per channel per scanline, so its simply not possible to watch Channel on every iteration. Since this error is not repeatable in the same spot every time, im fairly sure that im just screwed. Thank you for all the suggestions.
I win because I have the most fun in life...
-
I appreciate the help, and im glad you havent just gotten fed up with me, but this loop is called per channel per scanline, so its simply not possible to watch Channel on every iteration. Since this error is not repeatable in the same spot every time, im fairly sure that im just screwed. Thank you for all the suggestions.
I win because I have the most fun in life...
Have you considered:
for (int Channel = 0; Channel < NumberOfChannels; Channel++)
{
if (-1 == Channel)
; // set breakpoint on this lineDat = (unsigned char\*)m\_Dither.Dat\[Channel\]; Out = (unsigned char\*)lpDithered->Data\[Channel\]; ChannelData = &(lpDthrCtrl->Data\[Channel\]); ...}
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
-
Have you considered:
for (int Channel = 0; Channel < NumberOfChannels; Channel++)
{
if (-1 == Channel)
; // set breakpoint on this lineDat = (unsigned char\*)m\_Dither.Dat\[Channel\]; Out = (unsigned char\*)lpDithered->Data\[Channel\]; ChannelData = &(lpDthrCtrl->Data\[Channel\]); ...}
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
all right! i finally got it! let me explain a little bit more about this problem. im working with my company's legacy code, and im not allowed to change it because "it works." what im supposed to be doing is writing an interface to this class. so i tracked the problem down, and it was a call to CoTaskMemAlloc(1024)... why the did they hard code this, and why cant i change it? so basically what i had to do was cut out the call to that function and manually reset all the memory calls to the proper sizes from the interface. i imagine this wasnt a problem when they were processing small images, but now they're using huge digital photo quality images, im tempted to tell my boss whats up, but then ill probably hear an ear full for working around their class that "just works." thanks for the help man.
I win because I have the most fun in life...
-
all right! i finally got it! let me explain a little bit more about this problem. im working with my company's legacy code, and im not allowed to change it because "it works." what im supposed to be doing is writing an interface to this class. so i tracked the problem down, and it was a call to CoTaskMemAlloc(1024)... why the did they hard code this, and why cant i change it? so basically what i had to do was cut out the call to that function and manually reset all the memory calls to the proper sizes from the interface. i imagine this wasnt a problem when they were processing small images, but now they're using huge digital photo quality images, im tempted to tell my boss whats up, but then ill probably hear an ear full for working around their class that "just works." thanks for the help man.
I win because I have the most fun in life...
So exactly how did allocating 1024 bytes, rather than some larger number, mess up what you were doing?
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
-
So exactly how did allocating 1024 bytes, rather than some larger number, mess up what you were doing?
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
it knew it was supposed to be accessing that memory, but it wasnt allocated properly, so it was overwriting into memory set aside for Channel and LengthInBytes. We (my cube mate, and i) stuck a whole bunch of _Asserts everywhere, and Channel never equaled -1, but as soon as the it set Out = (unsigned char*)lpDithered->Data[Channel]; Channel and LengthInBytes lost their value.
I win because I have the most fun in life...
-
VonHagNDaz wrote:
if (Channel = -1).
:wtf::omg: !!! man, it should be this :
if (Channel
**==**-1)by using
=instead of==, you're assigning it !
[VisualCalc][Binary Guide][CommDialogs] | [Forums Guidelines]
Actually, it should be written thus:
if (-1 == Channel)
so if you mistakenly use
=instead of==the compiler will puke. If you get in the habit of putting the constant on the left side of the equation it'll save you many headaches. -
Actually, it should be written thus:
if (-1 == Channel)
so if you mistakenly use
=instead of==the compiler will puke. If you get in the habit of putting the constant on the left side of the equation it'll save you many headaches.yeah, i know this, but I don't like it ! lol but for beginners, (for which the chance to fall in the trap is approaching the 100%), they should take this habbit...
[VisualCalc][Binary Guide][CommDialogs] | [Forums Guidelines]