ftell(3C)
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ftell function
Return the current byte position in a file.
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Calling Sequence
#include <stdio.h>
FILE *fp;
long position, ftell();
position = ftell(fp);
where position is the current byte position within a file.
fp is a pointer to an FILE stream.
Description
Use the ftell function to determine your current position in a
file. The include file stdio.h defines this function.
Returns
The ftell function returns the current position in a file, or -1
if an error occurs. Non-disk files will typically return -1.
Example
/* Program test for the ftell() function */
#include <stdio.h>
#define EOF -1
FILE *fp, *fopen();
int next;
long position, ftell();
main(argc, argv)
int argc;
char *argv[];
{
fp = fopen(argv[1], "r");
while ((next = getc(fp)) != EOF) {
putchar(next);
printf(" %ld ", position = ftell(fp));
}
DG/UX 4.00 Page 1
Licensed material--property of copyright holder(s)
ftell(3C)
}
A call to program test with the valid filename input_str, which
contains
My last byte.
generates the output
M 1 y 2 3 l 4 a 5 s 6 t 7 8 b 9 y 10 t 11 e 12 . 13
DG/UX 4.00 Page 2
Licensed material--property of copyright holder(s)