fopen, ifstream

[arenner]

I'm trying to open a text file and read its contents. Then I use the value in the text file as my "alpha".

 

I have implemented these methods:

 

1)

ifstream inFile("C:mcamxaxis_alignment.txt");

inFile>>alpha;

 

2)

FILE *instream;

instream=fopen("C:mcamxaxis_alignment.txt","r");

fscanf(instream,"%lf",α);

 

I put these two methods into m_main of the standard chook wizard. But when I run the chook it is not opening the file. I put an if(instream != NULL) and placed the function using alpha inside it, and the function is never performed. So I know that instream is NULL. But I cannot see why. Any help is appreciated.

[markov]

Stupid question, but have you checked that the file exists in that location?

 

Check the errno value, it may give you some indication. Also, see what GetLastError() returns as another source of information.

[Takashi Sato from Ai Solutions.]

It seems you are trying to read a text data from text file.

 

If you use ifstream, use getline function, and read a line text to a buffer.

 

and if you use fopen, try "rt". it is read text mode.

 

fopen("C:mcamxaxis_alignment.txt","rt");

 

HTH

[markov]

Text mode is the default, does not need to be explicitly specified. And from what I undestand, the problem is in fopen function returning NULL before any read happens, so I do not think this would help.

[Takashi Sato from Ai Solutions.]

arg,

an another thing in my mind is locale thing.

but when you dont use multibyte characters, it wont be a problem.

 

setlocale(LC_CTYPE, "")

[arenner]

Thank you both for chiming in. I was hoping you two would be the ones to provide input.

 

1) I have checked, and yes the file exists, is a text file, and has read and write permissions (and is in that exact location). I also put it in the same folder as main just for good measure.

 

markov can you tell me what you mean by "errno" and where to find that? I found a site to do GetLastError() and may try that.

 

2) As markov says MasterShake, I'm certain it isn't even reading the file yet because it's registering the stream as NULL. So I don't know if that will change anything:(

 

I could use a little more info on setlocale(), I'm not sure I understand how to debug with that?

 

Either way, thanks again guys.

[arenner]

Oh, the other thing I forgot to ask, is there any reason I can't do this inside of m_main?

 

I use the wizard's m_main function:

 

extern "C" __declspec(dllexport) int m_main (int not_used)

 

So all of the code I mention above is inside that function. I don't think this would be a problem, but wanted to mention it just in case.

[markov]

errno is just an integer variable (or a macro that results in the _errno() function call) and gives you the error code of the last C runtime function call that failed. GetLastError() is a Win32 API that gives you the error code of the last failed system call. Just print the errors, probably using a MessageBox call, with something like this:

code:

---

MessageBox(..., strerror(errno), ...);

char s[100];

FormatMessage(..., GetLastError(), ... , s, ...);

MessageBox(..., s, ..);

---

[arenner]

Ok, thanks. I found something on msdn:

 

http://msdn2.microsoft.com/en-us/library/ms680582.aspx

 

I copied that into my main.cpp for the chook. But I don't think I called it right, cause it didn't give me a messagebox. I'm not good enough with programming yet to know how else to implement that. Thanks for the info.

[markov]

The sample from MSDN should work.

 

I have another idea. Are you by any chance compiling with VS2003, and creating C-hook for X2? If that is the case, you have a "complicated" C-hook, as described in the other thread. There may be a chance it would still work if you link it statically to the C runtime.

[arenner]

I was with you markov up to the last sentence. I'm trying to get 2005, so I'm sure VS 2003 isn't helping. I have no clue what you means by statically link it to the C runtime (not a programmer, sorry). Thanks for the ideas:)

[markov]

Somewhere in the project properties (I am not at my computer now so I can not check) there is an option to select the runtime library. If it does not use a variation of the word "static", then it probably says "libcmt.lib".

 

Note that it is not advisable to run in the multiple runtime environments (which is what you are going to end up with if you statically link you C-hook) even if it appears to work (you may discover subtle problems later), but you probably do not have an option.

[arenner]

Ok, thanks markov. In the C/C++ folder->Code Generation->Runtime Library, I see "Multi-threaded Debug DLL (/MDd)". I don't think this is the right location though, I didn't see anything saying static or libcmt.lib. I think I'm looking in the wrong place.

[markov]

OK, you found the right place. Select "Multi-threaded (/MT)" and check if it works.

[arenner]

Hmm. I finally picked up VS 2005. I switched it to (/MT) but that didn't work. It said it only could accept (/Md) for AFXDLLs.

[markov]

But you do not need MFC for you simple program that just opens a file.

 

In any case it is irrelevant now that you have VS2005. If my theory was correct, the C-hook will be able to open that file now.

[arenner]

Oh, yeah, that part should be simple. But that's just part of Chooks I'm developing to automate some positioning of CAD models in Mastercam with data generated from external programs.

 

I tried building with VS 2005. And didn't use fscanf or fopen, but I used ifstream, and it now is reading from my text file just fine. Thanks for your help, but I'm not sure what changed.

[markov]

quote:

---

Thanks for your help, but I'm not sure what changed.

---

A lot, namely the compiler and more importantly the header files! What was happening here is that you were (indirectly) using structure declarations from one version of the header files to access code (in the runtime DLL) that was compiled with a different version of the header files and different compiler.

[arenner]

Oh I see. And by that I mean it's what I didn't see, the behind the scenes stuff that I know nothing about. Thanks for the info. I didn't really put enough emphasis on the problems created with my compiling with 2003, and X2 compiled with 2005. Thanks again.