| 1 | #if defined(LIBC_SCCS) && !defined(lint) |
| 2 | static char sccsid[] = "@(#)ftell.c 5.2 (Berkeley) %G%"; |
| 3 | #endif LIBC_SCCS and not lint |
| 4 | |
| 5 | /* |
| 6 | * Return file offset. |
| 7 | * Coordinates with buffering. |
| 8 | */ |
| 9 | |
| 10 | #include <stdio.h> |
| 11 | long lseek(); |
| 12 | |
| 13 | |
| 14 | long ftell(iop) |
| 15 | register FILE *iop; |
| 16 | { |
| 17 | register long tres; |
| 18 | register adjust; |
| 19 | |
| 20 | if (iop->_cnt < 0) |
| 21 | iop->_cnt = 0; |
| 22 | if (iop->_flag&_IOREAD) |
| 23 | adjust = - iop->_cnt; |
| 24 | else if (iop->_flag&(_IOWRT|_IORW)) { |
| 25 | adjust = 0; |
| 26 | if (iop->_flag&_IOWRT && iop->_base && (iop->_flag&_IONBF)==0) |
| 27 | adjust = iop->_ptr - iop->_base; |
| 28 | } else |
| 29 | return(-1); |
| 30 | tres = lseek(fileno(iop), 0L, 1); |
| 31 | if (tres<0) |
| 32 | return(tres); |
| 33 | tres += adjust; |
| 34 | return(tres); |
| 35 | } |