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command 2> error.log
Search Windows Help (Start Menu -> Help) for "Using command redirection operators".
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STDIN 0 Keyboard input
STDOUT 1 Output to the Command Prompt window
STDERR 2 Error output to the Command Prompt window
Florin Crişan
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I have the following code to read data from a list of files. The code read the first file and read the data correctly. I used break point debug and found at "fclose(f_ptr2)" giving error: "Access Violation"
Please help and many thanks to Gurus.
FILE *f_ptr2;
//
for (int ii=0;ii
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You really need to debug this yourself if you can't post relevant code.
Things to check for:
1) fopen() returning NULL
2) Any of the fscanf() calls returning 0, EOF, or some other unexpected value
3) buffer overrun(s) in any of the fscanf calls - there's safe versions of fscanf() to help
catch/prevent these
Mark
Mark Salsbery
Microsoft MVP - Visual C++
![Java | [Coffee]](https://www.codeproject.com/script/Forums/Images/coffee.gif)
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I checked that the program open the fist file without problem in the loop and the program also read the data of the first file correctly, but it can not close the file - giving error message like: "Access Violation or memery can not be read"
I need the program to close the file and open the next file in the array of the file using the same file pointer p_ftr2.
Thanks a lots for looking onto the problem.
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fopen() may fail; it will indicate that by returning NULL.
all subsequent file operations must be qualified by f_ptr2!=NULL
and yes, it is a pitty fclose does not perform a zero test internally...
if this does not solve it, please show all the relevant code, that is actual code,
and please please use PRE tags so it is readable.
Luc Pattyn [Forum Guidelines] [My Articles]
this months tips:
- before you ask a question here, search CodeProject, then Google
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get
- use PRE tags to preserve formatting when showing multi-line code snippets
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void CBlast_vib_procDlg::Next()
{
FILE *f_ptr1;
FILE *f_ptr2;
const int MAX=15;
CBlast_vib_procDlg rr;
float north[2000];
float east[2000];
float elv[2000];
CString fname[2000];
char buffer[MAX];
UpdateData();
if(m_outputFileName == "" )
{
MessageBox("All file names have to be typed in !");
rr.m_outputFileName = m_outputFileName;
rr.DoModal();
UpdateData(false);
}
#define BUFSIZE MAX_PATH
WIN32_FIND_DATA FindFileData;
LPTSTR DirSpec;
HANDLE hFind = INVALID_HANDLE_VALUE;
CString fileName[2000];
int i=0;
DirSpec = (LPTSTR) malloc (BUFSIZE);
DirSpec=TEXT("*.txt");
hFind = FindFirstFile(DirSpec, &FindFileData);
fileName[0]=FindFileData.cFileName;
while (FindNextFile(hFind, &FindFileData) != 0)
{
i+=1;
fileName[i]=FindFileData.cFileName;
}
int nfile=i;
FindClose(hFind);
for (int ii=0;ii<nfile;ii++)
{
if((f_ptr2 = fopen(fileName[ii],"r")) == NULL) {
MessageBox("output file open problems !");
}
fscanf( f_ptr2,"%s %s %s\n",buffer,buffer,fname[ii].GetBuffer(MAX_PATH));
fname[ii].ReleaseBuffer();
fscanf( f_ptr2,"%s %s %s %s %s\n",buffer,buffer,buffer,buffer,buffer);
fscanf( f_ptr2,"%s %s %s\n",buffer,buffer,buffer);
fscanf( f_ptr2,"%s %s %s\n",buffer,buffer,buffer);
fscanf( f_ptr2,"%s %s %s %s\n",buffer,buffer,buffer,buffer);
fscanf( f_ptr2,"%s %s %s %s\n",buffer,buffer,buffer,buffer);
fscanf( f_ptr2,"%s %s %f\n",buffer,buffer,&elv[ii]);
fscanf( f_ptr2,"%s %s %s %s\n",buffer,buffer,buffer,buffer);
fscanf( f_ptr2,"%s %s %s %s\n",buffer,buffer,buffer,buffer);
fscanf( f_ptr2,"%s %s %s %s\n",buffer,buffer,buffer,buffer);
fscanf( f_ptr2,"%s %s %s %s %s\n",buffer,buffer,buffer,buffer,buffer);
fscanf( f_ptr2,"%s %s %s\n",buffer,buffer,buffer);
fscanf( f_ptr2,"%s %s %f\n",buffer,buffer, &east[ii]);
fscanf( f_ptr2,"%s %s %f\n",buffer,buffer,&north[ii]);
fclose(f_ptr2);
}
if((f_ptr1 = fopen(m_outputFileName,"w")) == NULL) {
MessageBox("output file open problems !");
rr.m_outputFileName = m_outputFileName;
rr.DoModal();
UpdateData(false);
}
fprintf (f_ptr1, "%i\n", nfile);
char * tittle = "number of monitors";
fprintf (f_ptr1, "%i\n", nfile);
char * tittle_item = "fineName Easting(m) Northing(m) elv(m)";
fprintf (f_ptr1, "%s\n", tittle_item);
for (ii=0;ii<nfile;ii++)
{
fprintf (f_ptr1, "%s %f %f %f\n", fname[ii],east[ii],north[ii],elv[ii]);
}
fclose( f_ptr1);
CDialog::OnOK();
}
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Hi,
[Added] ignore this reply, it is wrong! [/added]
there is a problem in fileName[i]=FindFileData.cFileName;
this line does NOT copy the filename, it copies the pointer to the cFileName field
in your unique FindFileData struct, hence in all iterations it will point to the
buffer containing the last data written into it.
If you want to hold all the different filenames, you must copy them, which you could
do with strcpy() or strncpy().
BTW: your NULL test shows a MessageBox but then continues the program execution,
which will result in failure of fscanf and/or fclose. The right way to handle this is
to have an if-then-else with all file actions (fscanf/fclose) in one part, and the
error handling (I do not really like MessageBox !) in the other part.
-- modified at 13:39 Monday 26th November, 2007
Luc Pattyn [Forum Guidelines] [My Articles]
this months tips:
- before you ask a question here, search CodeProject, then Google
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get
- use PRE tags to preserve formatting when showing multi-line code snippets
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Luc Pattyn wrote: there is a problem in fileName[i]=FindFileData.cFileName;
this line does NOT copy the filename, it copies the pointer to the cFileName field
in your unique FindFileData struct, hence in all iterations it will point to the
buffer containing the last data written into it.
If you want to hold all the different filenames, you must copy them, which you could
do with strcpy() or strncpy().
Not necessary at all. The statement is correct, since CString has an assignment operator that internally does the copying. fileName[0], fileName[1], fileName[2], etc will each contain different data.
"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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My mistake, was looking at it as a C function. 
Luc Pattyn [Forum Guidelines] [My Articles]
this months tips:
- before you ask a question here, search CodeProject, then Google
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get
- use PRE tags to preserve formatting when showing multi-line code snippets
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While it (probably) has nothing to do with your problem, I'd offer:
1) Don't post commented-out code. It just makes that much more for us to have to read/ignore.
2) Since you are using MFC, why not take advantage of CStdioFile, AfxMessagBox(), and CFileFind?
That said, do the first 2-4 "columns" in your input file contain more than 14 characters? If so, buffer will not hold them all.
If there are more than 2000 files in the folder pointed to by DirSpec, you'll have obvious trouble.
Your very last for() loop is using ii and II. Is that intentional?
mrby123 wrote: DirSpec = (LPTSTR) malloc (BUFSIZE);
DirSpec=TEXT("*.txt");
The address assigned to DirSpec (from malloc()) has been changed, and a subsequent call to free() would fail.
Consider:
CStringArray fileNames;
CFileFind fileFind;
BOOL bFound = fileFind.FindFile("*.txt");
while (bFound)
{
bFound = fileFind.FindNextFile();
fileNames.Add(fileFind.GetFilePath());
}
fileFind.Close();
for (int ii = 0; ii < fileNames.GetSize(); ii++)
{
CString fileName = fileNames.GetAt(ii);
CStdioFile fileIn;
if (fileIn.Open(fileName, CFile::modeRead))
{
CString line;
fileIn.ReadString(line);
fileIn.Close();
}
}
CStdioFile fileOut;
if (fileOut.Open(m_outputFileName, CFile::modeWrite))
{
CString str;
str.Format("%d\n", fileNames.GetSize());
fileOut.WriteString(str);
fileOut.WriteString(str);
fileOut.WriteString("fineName Easting(m) Northing(m) elv(m)\n");
for (int ii = 0; ii < fileNames.GetSize(); ii++)
{
CString fileName = fileNames.GetAt(ii);
str.Format("%s %f %f %f\n", fileName, east[ii], north[ii], elv[ii]);
fileOut.WriteString(str);
}
fileOut.Close();
}
"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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DavidCrow wrote: If so, buffer will not hold them all.
And worse, the data may spill and overwrite whatever is adjacent to buffer, causing
unpredictable errors. Overwriting a pointer is likely to result in "Access violation".
The present code is unsafe.
Luc Pattyn [Forum Guidelines] [My Articles]
this months tips:
- before you ask a question here, search CodeProject, then Google
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get
- use PRE tags to preserve formatting when showing multi-line code snippets
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David,
You solve my problem. You are right that I have a test which is longer than 15 characters in the data file.
Thanks alots.
Ruilin
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You could have possibly found the problem sooner by using the debugger to step over each of the calls to fscanf() and watch the value of f_ptr2. I suspect it was changed by the time fclose() was called.
"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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DavidCrow wrote: You could have possibly found the problem sooner by using the debugger
Surely YOU jest 
Mark Salsbery
Microsoft MVP - Visual C++
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No really, I'm dead serious. Science has proven that the debugger really does add years to your life, make you look taller, help you find problems quicker.
"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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I think this statement might have the problem.
fscanf( f_ptr2,"%s %s %s\n",buffer,buffer,fname[ii].GetBuffer(MAX_PATH));
Here one of the pointer is taken using GetBuffer of CString. I think it is not the correct way of geting the pointer of CString memory and copying value in it like character array. Taking the value in character array and then assigning it to CString might be better option. Something like this.
char sTemp[500];
fscanf( f_ptr2,"%s %s %s\n",buffer,buffer, sTemp);
fname[ii] = sTemp;
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Sunil Shindekar wrote: I think this statement might have the problem.
fscanf( f_ptr2,"%s %s %s\n",buffer,buffer,fname[ii].GetBuffer(MAX_PATH));
While it's awkward looking, there is nothing wrong with it.
Sunil Shindekar wrote: Taking the value in character array and then assigning it to CString might be better option.
Different? Yes. Better? No.
"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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GetBuffer returns the pointer to the memory which is enough to store the current string assigned to the CString object. You are using the same pointer to read the data from the file. If the data is too large to store in the currently allocated memory for the pointer by the CString, then there will be memory overrun. It can cause overwriting the values of other memory locations which may or may not include file pointer also or FILE structure also.
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Sunil Shindekar wrote: If the data is too large to store in the currently allocated memory for the pointer by the CString, then there will be memory overrun. It can cause overwriting the values of other memory locations which may or may not include file pointer also or FILE structure also.
Aand how is your suggestion of using char sTemp[500] any better?
"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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I have the following code to read data from a list of files. The code read the first file and read the data correctly. I used break point debug and found at "fclose(f_ptr2)" giving error: "Access Violation or memery can not be read"
//
FILE *f_ptr2;
//
//
for (int ii=0;ii {
//
f_ptr2 = fopen(fileName[ii],"r");
//
fscanf( f_ptr2,"%s %s %s\n",buffer,buffer,fname[ii].GetBuffer(MAX_PATH)); fname[ii].ReleaseBuffer();
fscanf( f_ptr2,"%s %s %f\n",buffer,buffer, &east[ii]); //easting
fscanf( f_ptr2,"%s %s %f\n",buffer,buffer,&north[ii]); //northing
fclose(f_ptr2);
}
//
Please help and thanks
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You asked this yesterday, and you still haven't fixed your code so we can read it all.
Is f_ptr2 valid? I don't see any check for NULL.
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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In fact, I have:
if((f_ptr2 = fopen(fileName[ii],"r")) == NULL) {
MessageBox("output file open problems !");
}
It seems that the fopen has no problem.
Thanks
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What are buffer, fname, east, and north?
"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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They are:
const int MAX=15;
float north[2000];
float east[2000];
float elv[2000];
CString fname[2000];
char buffer[MAX];
buffer is used to read data as dumy. The data never exceeds 15 characters. Thanks
In fact, the following code works fine and print all files of *.txt without an error message.
----------------------------------------------------
void CBlast_vib_procDlg::Next()
{
FILE *f_ptr1;
FILE *f_ptr2;
const int MAX=16;
CBlast_vib_procDlg rr;
//
float north[2000];
float east[2000];
float elv[2000];
CString fname[2000];
//
char buffer[MAX];
// TODO: Add your control notification handler code here
UpdateData();
if(m_outputFileName == "" )
{
MessageBox("All file names have to be typed in !");
rr.m_outputFileName = m_outputFileName;
rr.DoModal();
UpdateData(false);
}
#define BUFSIZE MAX_PATH
WIN32_FIND_DATA FindFileData;
LPTSTR DirSpec;
//
HANDLE hFind = INVALID_HANDLE_VALUE;
CString fileName[2000];
int i=0;
DirSpec = (LPTSTR) malloc (BUFSIZE);
DirSpec=TEXT("*.txt");
//
hFind = FindFirstFile(DirSpec, &FindFileData);
fileName[0]=FindFileData.cFileName;
//
while (FindNextFile(hFind, &FindFileData) != 0)
{
i+=1;
fileName[i]=FindFileData.cFileName;
}
int nfile=i;
FindClose(hFind);
// open output data file
if((f_ptr1 = fopen(m_outputFileName,"w")) == NULL) {
MessageBox("output file open problems !");
rr.m_outputFileName = m_outputFileName;
rr.DoModal();
UpdateData(false);
}
//
fprintf (f_ptr1, "%i\n", nfile);
for (int ii=0;ii
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Greetings!
I am looking for a Gantt chart control that can be used inside an ActiveX control developed in VB6 or VC++ 6. The control must allow me to draw tasks myself, and it must support drag-and-drop operations.
Here's the background: My company supplies annealing furnaces. A user stacks steel coils and drops a cover on them. Then they drop a furnace over the cover and heat the coils for the better part of the day. Then they take the furnace off and put a cooler on and cool the coils for several more hours. An annealing plant has several bases, furnaces and cooling covers, but fewer furnaces and covers than bases. Each base will be a resource on the chart. Each charge (stack of coils) will be a task. One color will be used for heating, and another for cooling. The caption for each task will include the charge number, furnace number and cooler number.
I have been working with the ActiveGanttVC control from SourceCodeStore.com, which is based in Bogota, Colombia. This control has a very nice API, including a set of events that I can handle to do my own drawing. The only problem is that despite several E-mails, I have never received a reply from this company. The US 800 number given on its "Contact Us" page belongs to a cruise line, completely mystifying some poor operator who wondered why I called them asking about an ActiveX control. I am really uncomfortable using this company's product. Can somebody recommend one where I might have some prayer of reaching a live person when I need to?
Thanks very much!
Rob Richardson
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