Normally a file pointer is NOT a "stream". A file pointer is defined as the current position in the file maintained for a given file descriptor - the OS keeps track of it. What I think you meant by file pointer is the "stream" above.
ftell() returns the position of the file pointer relative to the start of the file.
void main()
{
int a={1,2,3,4,5,6,7,8,9,10};
int *p=a;
int *q=&a;
cout<<q-p+1<<endl;
}
The output is 10, how?
if we give cout<<q it will print the address, value won't print....
if we give cout<<p it will print the address, value won't print....
p has the base addr; q... (1 Reply)
hi all:
bankpro again,
i want to open a file and close it after an hour (i.e open and close the file ptr)
In the mean time i will be executing my jobs using the shell (CommandInterpreter).
plz help... :cool: (3 Replies)
Hi everybody,
i am newbie to unix and confused with file pointers and file descripters.
could anyone help me to clear my doubts ..
when we call unix system calls to create a file then we are dealing wih file descripters
i think file descripters are also normals file as stored inhard disks... (1 Reply)
can u tell me the reson that why we should not delete a pointer twice.?
if we delete ponter twice then what happen and why this happen
Regards,
Amit (2 Replies)
I have a text file that has blocks of text. Each block starts with ### and ends with End_###.
I wrote a perl script to search a string from line 2 (ignore any line starts with ###) of each block
if matched, need to print that whole block. According to the input file in below, it will print... (5 Replies)
Hello experts,
I ve a text file I want to go to particular line . what is the best way to do this in c ?
I am tried as follows
fseek ( fh, pos, SEEK_SET);
but this functions moves the file pointer according to a number of bytes. Unfortunately I don't know the exact byte... (7 Replies)
If one wants to get a start address of a array or a string or a block of memory via a function, there are at least two methods to achieve it:
(1) one is to pass a pointer-to-pointer parameter, like:
int my_malloc(int size, char **pmem)
{
*pmem=(char *)malloc(size);
if(*pmem==NULL)... (11 Replies)
hi....,
can anyone tell me what is the exact difference between file descriptor and file pointer...... and why file descriptor takes integer value???:confused: (10 Replies)
if i declare both but don't input any variables what values will the int array and file pointer array have on default, and if i want to reset any of the elements of both arrays to default, should i just set it to 0 or NULL or what? (1 Reply)
Discussion started by: omega666
1 Replies
LEARN ABOUT REDHAT
fgetpos
FSEEK(3) Linux Programmer's Manual FSEEK(3)NAME
fgetpos, fseek, fsetpos, ftell, rewind - reposition a stream
SYNOPSIS
#include <stdio.h>
int fseek(FILE *stream, long offset, int whence);
long ftell(FILE *stream);
void rewind(FILE *stream);
int fgetpos(FILE *stream, fpos_t *pos);
int fsetpos(FILE *stream, fpos_t *pos);
DESCRIPTION
The fseek function sets the file position indicator for the stream pointed to by stream. The new position, measured in bytes, is obtained
by adding offset bytes to the position specified by whence. If whence is set to SEEK_SET, SEEK_CUR, or SEEK_END, the offset is relative to
the start of the file, the current position indicator, or end-of-file, respectively. A successful call to the fseek function clears the
end-of-file indicator for the stream and undoes any effects of the ungetc(3) function on the same stream.
The ftell function obtains the current value of the file position indicator for the stream pointed to by stream.
The rewind function sets the file position indicator for the stream pointed to by stream to the beginning of the file. It is equivalent
to:
(void)fseek(stream, 0L, SEEK_SET)
except that the error indicator for the stream is also cleared (see clearerr(3)).
The fgetpos and fsetpos functions are alternate interfaces equivalent to ftell and fseek (with whence set to SEEK_SET), setting and storing
the current value of the file offset into or from the object referenced by pos. On some non-UNIX systems an fpos_t object may be a complex
object and these routines may be the only way to portably reposition a text stream.
RETURN VALUE
The rewind function returns no value. Upon successful completion, fgetpos, fseek, fsetpos return 0, and ftell returns the current offset.
Otherwise, -1 is returned and the global variable errno is set to indicate the error.
ERRORS
EBADF The stream specified is not a seekable stream.
EINVAL The whence argument to fseek was not SEEK_SET, SEEK_END, or SEEK_CUR.
The function fgetpos, fseek, fsetpos, and ftell may also fail and set errno for any of the errors specified for the routines fflush(3),
fstat(2), lseek(2), and malloc(3).
CONFORMING TO
The fgetpos, fsetpos, fseek, ftell, and rewind functions conform to ANSI X3.159-1989 (``ANSI C'').
SEE ALSO lseek(2), fseeko(3)BSD MANPAGE 1993-11-29 FSEEK(3)