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ftell() Get Current File Pointer Position
#include <stdio.h>
long ftell(stream);
FILE *stream; Pointer to file structure
ftell() returns the current position of the file pointer associated
with 'stream'. The position is measured in bytes from the beginning
of the file.
Returns: The current pointer position, if successful. -1L is
returned on error. An undefined value is returned on
devices incapable of seeking, or when 'stream' does not
refer to an open file.
Notes: Due to the CR-LF translation performed for files opened
in text mode, the value returned by ftell() may not be
the correct physical offset. ftell() can be used together
with fseek() to correctly remember and return to file
locations.
-------------------------------- Example ---------------------------------
The following statements save the current position, move to the
beginning of the file, then return to the saved position.
#include <stdio.h>
FILE *stream;
long current_pos;
main()
{
If ((stream = fopen("new.dat","rb")) != NULL) {
current_pos = ftell(stream);
fseek(stream,0L,SEEK_SET);
.
.
.
fseek(stream,current_pos,SEEK_SET);
}
}
See Also:
fseek()
lseek()
tell()
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