diff options
| author | Michael Kerrisk <mtk.manpages@gmail.com> | 2007-05-18 16:06:42 +0000 |
|---|---|---|
| committer | Michael Kerrisk <mtk.manpages@gmail.com> | 2007-05-18 16:06:42 +0000 |
| commit | a1d5f77cc8a41c7c0ba751140e31b8b0e71fd091 (patch) | |
| tree | f55287808a115d93eb00615d65ca49ab9257bcf9 /man2/open.2 | |
| parent | 09a1235aaebbdd25fb974ab31e8bcdcf77e49031 (diff) | |
| download | man-pages-a1d5f77cc8a41c7c0ba751140e31b8b0e71fd091.tar.gz | |
Reordered sections to be more consistent, in some cases renaming
sections or shifting paragraphs between sections.
Diffstat (limited to 'man2/open.2')
| -rw-r--r-- | man2/open.2 | 103 |
1 files changed, 57 insertions, 46 deletions
diff --git a/man2/open.2 b/man2/open.2 index 2b6efd4f20..3360cf040e 100644 --- a/man2/open.2 +++ b/man2/open.2 @@ -369,46 +369,6 @@ return the new file descriptor, or \-1 if an error occurred (in which case, .I errno is set appropriately). -.SH NOTES -There are many infelicities in the protocol underlying NFS, affecting -amongst others -.BR O_SYNC " and " O_NDELAY . - -POSIX provides for three different variants of synchronised I/O, -corresponding to the flags \fBO_SYNC\fR, \fBO_DSYNC\fR and -\fBO_RSYNC\fR. -Currently (2.1.130) these are all synonymous under Linux. - -Note that -.BR open () -can open device special files, but -.BR creat () -cannot create them; use -.BR mknod (2) -instead. -.LP -On NFS file systems with UID mapping enabled, -.BR open () -may -return a file descriptor but e.g. -.BR read (2) -requests are denied -with \fBEACCES\fP. -This is because the client performs -.BR open () -by checking the -permissions, but UID mapping is performed by the server upon -read and write requests. - -If the file is newly created, its st_atime, st_ctime, st_mtime fields -(respectively, time of last access, time of last status change, and -time of last modification; see -.BR stat (2)) -are set -to the current time, and so are the st_ctime and st_mtime fields of the -parent directory. -Otherwise, if the file is modified because of the O_TRUNC flag, -its st_ctime and st_mtime fields are set to the current time. .SH ERRORS .TP .B EACCES @@ -523,12 +483,6 @@ The flag was specified, and an incompatible lease was held on the file (see .BR fcntl (2)). -.SH NOTES -Under Linux, the O_NONBLOCK flag indicates that one wants to open -but does not necessarily have the intention to read or write. -This is typically used to open devices in order to get a file descriptor -for use with -.BR ioctl (2). .SH "CONFORMING TO" SVr4, 4.3BSD, POSIX.1-2001. The @@ -540,6 +494,14 @@ flags are Linux specific. One may have to define the .B _GNU_SOURCE macro to get their definitions. +.SH NOTES +Under Linux, the +.B O_NONBLOCK +flag indicates that one wants to open +but does not necessarily have the intention to read or write. +This is typically used to open devices in order to get a file descriptor +for use with +.BR ioctl (2). .LP The (undefined) effect of .B O_RDONLY | O_TRUNC @@ -565,6 +527,55 @@ Older Linux kernels simply ignore this flag. One may have to define the .B _GNU_SOURCE macro to get its definition. +.PP +There are many infelicities in the protocol underlying NFS, affecting +amongst others +.BR O_SYNC " and " O_NDELAY . + +POSIX provides for three different variants of synchronised I/O, +corresponding to the flags \fBO_SYNC\fR, \fBO_DSYNC\fR and +\fBO_RSYNC\fR. +Currently (2.1.130) these are all synonymous under Linux. + +Note that +.BR open () +can open device special files, but +.BR creat () +cannot create them; use +.BR mknod (2) +instead. +.LP +On NFS file systems with UID mapping enabled, +.BR open () +may +return a file descriptor but e.g. +.BR read (2) +requests are denied +with \fBEACCES\fP. +This is because the client performs +.BR open () +by checking the +permissions, but UID mapping is performed by the server upon +read and write requests. + +If the file is newly created, its +.IR st_atime , +.IR st_ctime , +.I st_mtime +fields +(respectively, time of last access, time of last status change, and +time of last modification; see +.BR stat (2)) +are set +to the current time, and so are the +.I st_ctime +and +.I st_mtime +fields of the +parent directory. +Otherwise, if the file is modified because of the +.B O_TRUNC +flag, its st_ctime and st_mtime fields are set to the current time. .SH BUGS "The thing that has always disturbed me about O_DIRECT is that the whole interface is just stupid, and was probably designed by a deranged monkey |