diff options
Diffstat (limited to 'newlib/libc/stdio/fflush.c')
| -rw-r--r-- | newlib/libc/stdio/fflush.c | 40 |
1 files changed, 36 insertions, 4 deletions
diff --git a/newlib/libc/stdio/fflush.c b/newlib/libc/stdio/fflush.c index 2286e3878..a4e639e72 100644 --- a/newlib/libc/stdio/fflush.c +++ b/newlib/libc/stdio/fflush.c @@ -17,19 +17,32 @@ /* FUNCTION -<<fflush>>---flush buffered file output +<<fflush>>, <<fflush_unlocked>>---flush buffered file output INDEX fflush INDEX + fflush_unlocked +INDEX _fflush_r +INDEX + _fflush_unlocked_r ANSI_SYNOPSIS #include <stdio.h> int fflush(FILE *<[fp]>); + #define _BSD_SOURCE + #include <stdio.h> + int fflush_unlocked(FILE *<[fp]>); + + #include <stdio.h> int _fflush_r(struct _reent *<[reent]>, FILE *<[fp]>); + #define _BSD_SOURCE + #include <stdio.h> + int _fflush_unlocked_r(struct _reent *<[reent]>, FILE *<[fp]>); + DESCRIPTION The <<stdio>> output functions can buffer output before delivering it to the host system, in order to minimize the overhead of system calls. @@ -45,9 +58,18 @@ descriptor, set the position of the file descriptor to match next unread byte, useful for obeying POSIX semantics when ending a process without consuming all input from the stream. -The alternate function <<_fflush_r>> is a reentrant version, where the -extra argument <[reent]> is a pointer to a reentrancy structure, and -<[fp]> must not be NULL. +<<fflush_unlocked>> is a non-thread-safe version of <<fflush>>. +<<fflush_unlocked>> may only safely be used within a scope +protected by flockfile() (or ftrylockfile()) and funlockfile(). This +function may safely be used in a multi-threaded program if and only +if they are called while the invoking thread owns the (FILE *) +object, as is the case after a successful call to the flockfile() or +ftrylockfile() functions. If threads are disabled, then +<<fflush_unlocked>> is equivalent to <<fflush>>. + +The alternate functions <<_fflush_r>> and <<_fflush_unlocked_r>> are +reentrant versions, where the extra argument <[reent]> is a pointer to +a reentrancy structure, and <[fp]> must not be NULL. RETURNS <<fflush>> returns <<0>> unless it encounters a write error; in that @@ -57,6 +79,8 @@ PORTABILITY ANSI C requires <<fflush>>. The behavior on input streams is only specified by POSIX, and not all implementations follow POSIX rules. +<<fflush_unlocked>> is a BSD extension also provided by GNU libc. + No supporting OS subroutines are required. */ @@ -65,6 +89,12 @@ No supporting OS subroutines are required. #include <errno.h> #include "local.h" +#ifdef __IMPL_UNLOCKED__ +#define _fflush_r _fflush_unlocked_r +#define fflush fflush_unlocked +#endif + +#ifndef __IMPL_UNLOCKED__ /* Flush a single file, or (if fp is NULL) all files. */ /* Core function which does not lock file pointer. This gets called @@ -217,6 +247,8 @@ _DEFUN(__sflushw_r, (ptr, fp), } #endif +#endif /* __IMPL_UNLOCKED__ */ + int _DEFUN(_fflush_r, (ptr, fp), struct _reent *ptr _AND |