1 /*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Chris Torek. 7 * 8 * %sccs.include.redist.c% 9 */ 10 11 #if defined(LIBC_SCCS) && !defined(lint) 12 static char sccsid[] = "@(#)wsetup.c 5.1 (Berkeley) 01/20/91"; 13 #endif /* LIBC_SCCS and not lint */ 14 15 #include <stdio.h> 16 #include "local.h" 17 18 /* 19 * Various output routines call wsetup to be sure it is safe to write, 20 * because either _flags does not include __SWR, or _buf is NULL. 21 * _wsetup returns 0 if OK to write, nonzero otherwise. 22 */ 23 __swsetup(fp) 24 register FILE *fp; 25 { 26 /* make sure stdio is set up */ 27 if (!__sdidinit) 28 __sinit(); 29 30 /* 31 * If we are not writing, we had better be reading and writing. 32 */ 33 if ((fp->_flags & __SWR) == 0) { 34 if ((fp->_flags & __SRW) == 0) 35 return (EOF); 36 if (fp->_flags & __SRD) { 37 /* clobber any ungetc data */ 38 if (HASUB(fp)) 39 FREEUB(fp); 40 fp->_flags &= ~(__SRD|__SEOF); 41 fp->_r = 0; 42 fp->_p = fp->_bf._base; 43 } 44 fp->_flags |= __SWR; 45 } 46 47 /* 48 * Make a buffer if necessary, then set _w. 49 */ 50 if (fp->_bf._base == NULL) 51 __smakebuf(fp); 52 if (fp->_flags & __SLBF) { 53 /* 54 * It is line buffered, so make _lbfsize be -_bufsize 55 * for the putc() macro. We will change _lbfsize back 56 * to 0 whenever we turn off __SWR. 57 */ 58 fp->_w = 0; 59 fp->_lbfsize = -fp->_bf._size; 60 } else 61 fp->_w = fp->_flags & __SNBF ? 0 : fp->_bf._size; 62 return (0); 63 } 64