Need help in reading from file.


I have to read the contents of a text file into a char* variable. I am using visual c++ 6.0 and following is the code snippet-

#include <stdio.h>

static char* readFromFile(const char* fname)

   FILE *stream;
   char* list;

   if( (stream = fopen( fname, "r+t" )) != NULL )
      /* Attempt to read */
         fread( list, sizeof( char ), 100000, stream );
         fclose( stream );

   return list;

But the fopen fails here. When I tried to debug, it asks me the path of fopen.c.
What am I missing here?

Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

if fopen fails you don't need debug fopen.c but look for the error code.

The error you can get from the global variable  errno  that can be evaluated by including <errno.h>.

I suppose that you get errno==2 that is file not found and means that the file path in fname is incorrect.
Other error codes you may check in <winerror.h> where all windows error codes are listed with a comment.

You can easily find winerror.h by typing  #include <winerror.h> somewhere in your code and use context menu to open the document.

Hope, that helps

You need to alloc memory for list
Here is working code:

static char* readFromFile(const char* fname)

  FILE *stream;
  char* list = NULL;

  stream = fopen(fname, "r+t");

  if (stream != NULL)
     /* Attempt to read */
    list = new char[100000];
    fread(list, sizeof( char ), 100000, stream);

  return list;
OWASP: Threats Fundamentals

Learn the top ten threats that are present in modern web-application development and how to protect your business from them.

smita_rautAuthor Commented:

You were right. I got errno==3, i.e. path not found.
Coz' i had given a relative path like ..\\somefilename

Could you tell me how can we handle relative paths?
I tried _fullpath() to convert it to absolute path, but it gives incorrect result.
e.g. Actual path = C:\dir1\dir2\somefilename
I am at path = C:\dir1\dir2\dir3\
_fullpath() returns = C:\somefilename

I cannot use absolute path.
Can you help?

Relative path is ok, but you should know where your current directory is.

For VC projects current directory is the project directory if you start your program from Visual Studio.
You may evaluate the current directory path using GetCurrentDirectory() if you can include windows.h or _getcwd()  else.

Note, that all backslash characters explicitly defined must be typed twice within "" , e. g. "C:\\projects\\myfile.dat".
Or you may use forward slashes:  "C:/projects/myfile.dat"

Regards, Alex

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
>Could you tell me how can we handle relative paths?
Usually I inspect the path from which program was started.
And then create full filenames using the start path.

To get the start path use GetModuleFileName.
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.