Echelon i.LON SmartServer 2.0 - Manual (Page 249)

i.LON SmartServer 2.0 Programming Tools User’s Guide 235
fclose(pFile);
}
}
fseek()
You can use the fseek()method to set the position indicator associated with the a file stream to a
new position.
SYNTAX
int
fseek (FILE * stream, long int offset, int origin);
The stream parameter specifies a pointer to a FILE object that identifies the stream.
The offset parameter specifies the number of bytes to be offset from origin.
The origin parameter specifies the position from where offset is to be added. You can specify
the origin using one of the following three constants:
SEEK_SET
Beginning of the file
SEEK_CUR Current position of the file pointer
SEEK_END End of the file
If this position indicator has been moved successfully, this method returns a zero value.
Otherwise, it returns a non-zero value.
EXAMPLE
The following example demonstrates an fseek()method that moves the position indicator two
bytes from the beginning of an existing file.
FILE
* pFile;
fseek
(pFile , 2 , SEEK_SET);
fwrite()
You can use the fwrite()method to write an array of elements from a block of memory on the
SmartServer to the current position in a file stream.
SYNTAX
size_t
fwrite (const void * ptr, size_t size, size_t count, FILE *
stream);
The ptr parameter specifies the array of elements to be written to the file stream.
The size parameter specifies the size (in bytes) of each element to be written .
The count parameter specifies the number of elements to be written, each one with a size of size
bytes
.
The stream parameter specifies a pointer to a FILE object that specifies an output stream.
This method returns a size_t object, which is an integral data type that specifies the total
number of elements successfully written. If this number differs from count, an error has occurred.
EXAMPLE
The following example demonstrates an fwrite()method that writes some data to an existing
text file.
FILE *pFile;
char Filename[] = "/web/user/mUartTxFile.txt";
char buf[] = “Test String”; // output buffer
long len = 11;