fopen error & Assertion error - fgets.c

Hi there,

Firstly i hope this is the right board to post on, secondly apologies as im not an experianced programmer so may appear a little ignorant!

Ive written a 2D type sprite game in visual c++ in microsoft visual studio .NET which works fine within the Debug menu. Howerver i get my error when i try and run the .exe made for my game.

heres the error message

Code:

Debug Assertion Failed!

program: basejoystick.exe
File: fgets.c
Line: 60

Expression: str !=NULL

So my first error is due to not opening the file correctly i think, which gives me an error with the fgets function in my code. I worked this out by putting in the message box which tells me the target file isnt loaded.

Code:

     char	TheTargetFileNumber[15];
     char c = '\n';
     char fileInfo[50];
     char filename[50];
     
     strcpy(filename, "static_data1.csv"); //write the string of the filename to char filename
     staticData_f = fopen(filename, "r"); // open the file here

     if(staticData_f == NULL)
	{	MessageBox( NULL, TEXT("target file tracker.\n")\					       TEXT("not found\n")\
		       TEXT("."),  
		       TEXT("."), MB_ICONINFORMATION | MB_OK );
		return FALSE;
	}   // this message box will tell me if file not found

     fgets(fileInfo, sizeof(fileInfo), staticData_f);
     sscanf(fileInfo, "%15s", &TheTargetFileNumber);
     fclose(staticData_f);

in my file static_data1.csv i have this string

Code:

targets001.csv

I have my static_data1.csv file in the same directory as other files im opening and closing fine.

I would be greatfull if anyone could help me!! In other parts of my programe i open and close files in the same way with no problems?

Many thanks,
ANDY

> if(staticData_f == NULL)
If this is true, then use either
perror() to print a message on stderr, indicating why it failed
strerror() to get a char* pointer to a message indicating why it failed.

> targets001.csv
You do know this only just fits inside your buffer?

> sscanf(fileInfo, "%15s", &TheTargetFileNumber);
Unlike fgets, the field width in a scanf string doesn't make allowances for a \0, so this call has the capability of a 1 char overflow.
Also, you don't need the & when referring to char arrays.

Hi Salem,

Thanks for the speedy reply!! Thats a good idea with perror(), i guess i do something like this? (taken from MSDN libary)

Code:

int main( void )
{
   int  fh;

   if( _sopen_s( &fh, "NOSUCHF.ILE", _O_RDONLY, _SH_DENYNO, 0 ) != 0 )
   {
      /* Three ways to create error message: */
      perror( "perror says open failed" );
      printf( "strerror says open failed: %s\n",
         strerror( errno ) ); // C4996
      printf( _strerror( "_strerror says open failed" ) ); // C4996
      // Note: strerror and _strerror are deprecated; consider
      // using strerror_s and _strerror_s instead.
   }
   else
   {
      printf( "open succeeded on input file\n" );
      _close( fh );
   }
}

>> targets001.csv
>You do know this only just fits inside your buffer?

Yes thanks, basically i use this string written to file to keep track of which target file i want to open for my game. It can be any number from 001 to 100, then it loops back, so the string will never be larger than this.

>> sscanf(fileInfo, "%15s", &TheTargetFileNumber);
>Unlike fgets, the field width in a scanf string doesn't make allowances for a \0, so this call has >the capability of a 1 char overflow.
>Also, you don't need the & when referring to char arrays.

right okay. I guess this wont be a problem if my char TheTargetFileNumber[15] has 15 elements, good to know! Thanks for the & advice.

Ill have a look at the weekend and see if i make any progress.
Many thanks again!!

Hi guys,

Solved the problem! I hadn't put my targetfile tracking .csv file into my debug directory. Thanks for the advice, i should put the file opening checking code into my program anyways!

Many thanks,
Andy