diff options
Diffstat (limited to 'mysys/my_seek.c')
| -rw-r--r-- | mysys/my_seek.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/mysys/my_seek.c b/mysys/my_seek.c index 6f3c1349722..0d30ba203ae 100644 --- a/mysys/my_seek.c +++ b/mysys/my_seek.c @@ -23,7 +23,9 @@ my_off_t pos The expected position (absolute or relative) int whence A direction parameter and one of {SEEK_SET, SEEK_CUR, SEEK_END} - myf MyFlags Not used. + myf MyFlags MY_THREADSAFE must be set in case my_seek may be mixed + with my_pread/my_pwrite calls and fd is shared among + threads. DESCRIPTION The my_seek function is a wrapper around the system call lseek and @@ -54,9 +56,16 @@ my_off_t my_seek(File fd, my_off_t pos, int whence, Make sure we are using a valid file descriptor! */ DBUG_ASSERT(fd != -1); - - newpos= lseek(fd, pos, whence); - +#if defined(THREAD) && !defined(HAVE_PREAD) + if (MyFlags & MY_THREADSAFE) + { + pthread_mutex_lock(&my_file_info[fd].mutex); + newpos= lseek(fd, pos, whence); + pthread_mutex_unlock(&my_file_info[fd].mutex); + } + else +#endif + newpos= lseek(fd, pos, whence); if (newpos == (os_off_t) -1) { my_errno=errno; |