Re: Newbie's problem with fopen

Re: Newbie's problem with fopen

[Andre Kirchner]

Hi,

after a lot of debug I realize that there was nothing
wrong with fopen at logLink, but with opendir in
makeSubDir.
makeSubDir creates the following new subdirectory. All
subdirectories are like /home/andre/001,
/home/andre/002, ...
The problem is that even though a directory exists,
sometimes opendir can't open it, and returns NULL.
Does anyone have any idea about what could be wrong?

Thanks,

Andre

int makeSubDir( const char * theDirectory, char *
newSubDirectory )
{
	int subDir = 0;
	if( opendir( theDirectory ) == 0 )
		return( -1 );

	do
	{
		subDir++;
		sprintf( newSubDirectory, "%s/%03d", theDirectory,
subDir );
	}
	while( opendir( newSubDirectory ) );

	mkdir( newSubDirectory, S_IRUSR + S_IWUSR + S_IXUSR
);
	if( opendir( newSubDirectory ) == 0 )
		return( -1 );

	return( 0 );
}

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Re: Newbie's problem with fopen

[Eljay Love-Jensen]

Hi Andre,

When opendir fails, what is errno set to?

You can use errno to diagnose the problem.

The mnemonic identifier associated with the errno value is in errno.h header file.

That should tell you what went awry.

Note:  you seem to be failing to free the memory that opendir allocates.  Eventually, you will run out of heap.

HTH,
--Eljay

Re: Newbie's problem with fopen

[Ishwar Rattan]

Success in using library functions and system calls depends on
looking at the error returned (trap the error) and read the
man page. It has nothing to do with gcc.

-ishwar


On Fri, 26 Sep 2003, Andre Kirchner wrote:

> Hi,
>
> after a lot of debug I realize that there was nothing
> wrong with fopen at logLink, but with opendir in
> makeSubDir.
> makeSubDir creates the following new subdirectory. All
> subdirectories are like /home/andre/001,
> /home/andre/002, ...
> The problem is that even though a directory exists,
> sometimes opendir can't open it, and returns NULL.
> Does anyone have any idea about what could be wrong?
>
> Thanks,
>
> Andre
>
> int makeSubDir( const char * theDirectory, char *
> newSubDirectory )
> {
> 	int subDir = 0;
> 	if( opendir( theDirectory ) == 0 )
> 		return( -1 );
>
> 	do
> 	{
> 		subDir++;
> 		sprintf( newSubDirectory, "%s/%03d", theDirectory,
> subDir );
> 	}
> 	while( opendir( newSubDirectory ) );
>
> 	mkdir( newSubDirectory, S_IRUSR + S_IWUSR + S_IXUSR
> );
> 	if( opendir( newSubDirectory ) == 0 )
> 		return( -1 );
>
> 	return( 0 );
> }
>
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> Do you Yahoo!?
> The New Yahoo! Shopping - with improved product search
> http://shopping.yahoo.com
>

Newbie's problem with fopen

[Andre Kirchner]

Hi,

I made this function which should to log theLinks into
theLogFile, and return -1 if there was a problem, 0 if
theLinks has just been logged, or 1 if it was logged
before.
The problem is that somehow sometimes it cannot open
theFile even though theLogFile exits at the market
line.
Does anyone have any idea about the problem?
I'm using gcc on a Linux box if it matters.

Thanks a lot,

Andre


# include "logf.h"

int logLink( const char * theLink, const char *
theLogFile )
{
	char theLine[ 256 ];
	FILE * theFile;

	bzero( theLine, 256 );

	theFile = fopen( theLogFile, "r+" );
	if( theFile == NULL )
	{
		theFile = fopen( theLogFile, "w" );
		if( theFile == NULL )
It exits here-> return( -1 );
	}

	while( fgets( theLine, 256, theFile ) )
	{
		if( strcmp( theLine, theLink ) == 0 )
		{
			fclose( theFile );
			return( 1 );
		}
	}

	if( fprintf( theFile, "%s", theLink ) < 0 )
	{
		fclose( theFile );
		return( -1 );
	}
	fclose( theFile );

	return( 0 );
}

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