ftell, ftello - return a file offset in a stream
#include <stdio.h>
long ftell(FILE *stream);
[CX] off_t ftello(FILE *stream);
[CX] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers to the ISO C standard.The ftell() function shall obtain the current value of the file-position indicator for the stream pointed to by stream.
[CX] The ftello() function shall be equivalent to ftell(), except that the return value is of type off_t.
Upon successful completion, ftell() [CX] and ftello() shall return the current value of the file-position indicator for the stream measured in bytes from the beginning of the file.
Otherwise, ftell() [CX] and ftello() shall return -1, cast to long and off_t respectively, and set errno to indicate the error.
The ftell() [CX] and ftello() functions shall fail if:
- [EBADF]
- [CX] The file descriptor underlying stream is not an open file descriptor.
- [EOVERFLOW]
- [CX] For ftell(), the current file offset cannot be represented correctly in an object of type long.
- [EOVERFLOW]
- [CX] For ftello(), the current file offset cannot be represented correctly in an object of type off_t.
- [ESPIPE]
- [CX] The file descriptor underlying stream is associated with a pipe or FIFO.
The ftell() function may fail if:
- [ESPIPE]
- [CX] The file descriptor underlying stream is associated with a socket.
None.
None.
None.
None.
fgetpos(), fopen(), fseek() , lseek(), the Base Definitions volume of IEEE Std 1003.1-2001, <stdio.h>
First released in Issue 1. Derived from Issue 1 of the SVID.
Large File Summit extensions are added.
Extensions beyond the ISO C standard are marked.
The following new requirements on POSIX implementations derive from alignment with the Single UNIX Specification:
The ftello() function is added.
The [EOVERFLOW] error conditions are added.
An additional [ESPIPE] error condition is added for sockets.