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32 * @(#)fflush.c 8.1 (Berkeley) 6/4/93
33 * $FreeBSD: src/lib/libc/stdio/fflush.c,v 1.14 2007/01/09 00:28:06 imp Exp $
36 #include "namespace.h"
39 #include "un-namespace.h"
40 #include "libc_private.h"
44 static int sflush_locked(FILE *);
47 * Flush a single file, or (if fp is NULL) all files.
56 return (_fwalk(sflush_locked));
60 * There is disagreement about the correct behaviour of fflush()
61 * when passed a file which is not open for reading. According to
62 * the ISO C standard, the behaviour is undefined.
63 * Under linux, such an fflush returns success and has no effect;
64 * under Windows, such an fflush is documented as behaving instead
66 * Given that applications may be written with the expectation of
67 * either of these two behaviours, the only safe (non-astonishing)
68 * option is to return EBADF and ask that applications be fixed.
69 * But for c++ compatibility do not enforce it and match FreeBSD.
71 if ((fp->pub._flags & (__SWR | __SRW)) == 0)
74 retval = __sflush(fp);
80 * Flush a single file, or (if fp is NULL) all files.
89 return (_fwalk(sflush_locked));
90 if ((fp->pub._flags & (__SWR | __SRW)) == 0)
93 retval = __sflush(fp);
104 if ((t & __SWR) == 0)
107 if ((p = fp->_bf._base) == NULL)
110 n = fp->pub._p - p; /* write this much */
113 * Set these immediately to avoid problems with longjmp and to allow
114 * exchange buffering (via setvbuf) in user write function.
117 fp->pub._w = t & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
119 for (; n > 0; n -= t, p += t) {
120 t = _swrite(fp, (char *)p, n);
122 /* Reset _p and _w. */
123 if (p > fp->pub._p) {
124 /* Some was written. */
125 memmove(fp->pub._p, p, n);
127 if ((fp->pub._flags & (__SLBF | __SNBF)) == 0)
130 fp->pub._flags |= __SERR;
138 sflush_locked(FILE *fp)