/* @(#)fseek.c 1.3 */ /* 3.0 SID # 1.2 */ /*LINTLIBRARY*/ /* * Seek for standard library. Coordinates with buffering. */ #include <stdio.h> extern long lseek(); extern int fflush(); int fseek(iop, offset, ptrname) register FILE *iop; long offset; int ptrname; { register int c; long p; iop->_flag &= ~_IOEOF; if(iop->_flag & _IOREAD) { if(ptrname < 2 && iop->_base && !(iop->_flag&_IONBF)) { c = iop->_cnt; p = offset; if(ptrname == 0) p += (long)c-lseek(fileno(iop), 0L, 1); else offset -= (long)c; if(!(iop->_flag&_IORW) && c > 0 && p <= c && p >= iop->_base - iop->_ptr) { iop->_ptr += (int)p; iop->_cnt -= (int)p; return(0); } } if(iop->_flag & _IORW) { iop->_ptr = iop->_base; iop->_flag &= ~_IOREAD; } p = lseek(fileno(iop), offset, ptrname); iop->_cnt = 0; } else if(iop->_flag & (_IOWRT | _IORW)) { (void) fflush(iop); iop->_cnt = 0; if(iop->_flag & _IORW) { iop->_flag &= ~_IOWRT; iop->_ptr = iop->_base; } p = lseek(fileno(iop), offset, ptrname); } return((p == -1)? -1: 0); }