I am building a parser to parse different kind of files bytewise by using IO class.
However such class allows me (through the 'read' method) to read only amounts of bytes, and not bits.
I have just encountered a spec of a file where I need a bitwise reading, for example:
in this case I have to read 1 bit only at first, and then 15 or 7 afterwards.
Is there a way to do such thing with IO class? Thanks in advance!
Related
I would like to use Input / output module CR203x family with GoLang. The manuals all carry examples for CodeSys. Where can I find the CanOpen sequence to activate, write and read the connected probes?
Normally I would send a COB-ID and 8 bytes but I don't understand if TPDO1 or RPDO1 and even less what the 8 bytes mean. Thank you.
I downloaded the related .eds file but it doesn't help me much.
I don't make sure, but I think the ScadaLTS no have the modbus 16 function. I need write in 9 registers simultaneously, but the data type that ScadaLTS give does not satisfy my need. I did try to use the type data "fixed length string" but I can't represent the code 0 in ASCII, if I could, it would work.
Finally, I hope to find help and thank you very much in advance.
Modbus function 16 is writing multiple holding register address at once, we cannot write it one by one, and must use fc 16 code. But there is no option to write to multiple address at modbus datapoint. I need this feature also,
The Fortran program I am working is encountering a runtime error when processing an input file.
At line 182 of file ../SOURCE_FILE.f90 (unit = 1, file = 'INPUT_FILE.1')
Fortran runtime error: Bad value during integer read
Looking to line 182 I see a READ statement with an implicit/implied DO loop:
182: READ(IT4, 310 )((IPPRM2(IP,I),IP=1,NP),I=1,16) ! read 6 integers
183: READ(IT4, 320 )((PPARM2(IP,I),IP=1,NP),I=1,14) ! read 5 reals
Format statement:
310 FORMAT(1X,6I12)
When I reach this code in the debugger NP has a value of 2. I has a value of 6, and IP has a value of 67. I think I and IP should be reinitialized in the loop.
My problem is that when I try to step through in the debugger once I get to the READ statement it seems to execute and then throw the error. I'm not sure how to follow it as it reads. I tried stepping into the function, but it seems like that may be a difficult route to take since I am unfamiliar with the gfortran library. The input file looks OK, I think it should be read just fine. This makes me think this READ statement isn't looping as intended.
I am completely new to Fortran and implicit DO loops like this, but from what I can gather line 182 should read in 6 integers according to the format string #310. However, when I arrive NP has a value of 2 which makes me think it will only try to read 2 integers 16 times.
How can I debug this read statement to examine the values read into IPPARM as they are read from the file? Will I have to step through the Fortran library?
Any tips that can clear up my confusion regarding these implicit loops would be appreciated!
Thanks!
NOTE: I'm using gfortran/gcc and gdb on Linux.
Is there any reason you need specific formatting on the read? I would use READ(IT4, *) where feasible...
Later versions of gfortran support unlimited format reads (see link http://fortranwiki.org/fortran/show/Fortran+2008+status)
Then it may be helpful to specify
310 FORMAT("*(1X,6I12)")
Or for older compilers
310 FORMAT(1000(1X,6I12))
The variables IP and I are loop indices and so they are reinitialized by the loop. With NP=2 the first statement is going to read a total of 32 integers -- it is contributing to the determination the list of items to read. The format determines how they are read. With "1X,6I12" they will be read as 6 integers per line of the input file. When the first 6 of the requested 32 integers is read fron a line/record, Fortran will consider that line/record completed and advance to the next record.
With a format of "1X,6I12" the integers must be precisely arranged in the file. There should be a single blank, then the integers should each be right-justified in fields of 12 columns. If they get out of alignment you could get the wrong value read or a runtime error.
Well, I'm working on a project, in which I'm handling potentially big files, that I can't load into ram all at once, so I'm going to treat them like a CHS hard drive, and grab the data one 0x800 byte chunk at a time.
My problem is, I cannot find any functions in the WINAPI that allow me to read the data from a file I've opened with CreateFile, starting at an offset.
And yes, it must be a WINAPI function, and no, I do not want to map the whole file into memory.
Thanks much, Bradley.
Use ReadFile with SetFilePointer
HI all,
I am doing serial port communication program. How do I achieve the following.
Need to know number bytes available for reading.
Flushing
Note: I am creating File with Overlapped option.
thanks in advance
~ Johnnie
You are trying to query the number of bytes available first, and then read them. The standard way would be to just allocate a buffer (say 1000 chars), then call ReadComm() which tells you how many bytes were actually used (e.g. less than or equal to 1000).
You can flush the buffer of serial io using FlushFileBuffers() (http://msdn.microsoft.com/en-us/library/aa364439%28VS.85%29.aspx) but since you want asynchronous IO, you probably only want to do that when you have written to a file and then want to move the file (certainly not on every call to WriteComm()).
More info:
http://msdn.microsoft.com/en-us/library/ms810467.aspx