diff options
Diffstat (limited to 'lib/kernel/doc/src/file.xml')
| -rw-r--r-- | lib/kernel/doc/src/file.xml | 59 |
1 files changed, 58 insertions, 1 deletions
diff --git a/lib/kernel/doc/src/file.xml b/lib/kernel/doc/src/file.xml index 50f9722a1c..a9ceac0bcf 100644 --- a/lib/kernel/doc/src/file.xml +++ b/lib/kernel/doc/src/file.xml @@ -62,6 +62,25 @@ time() = {{Year, Month, Day}, {Hour, Minute, Second}} </section> <funcs> <func> + <name>advise(IoDevice, Offset, Length, Advise) -> ok | {error, Reason}</name> + <fsummary>Predeclare an access pattern for file data</fsummary> + <type> + <v>IoDevice = io_device()</v> + <v>Offset = int()</v> + <v>Length = int()</v> + <v>Advise = posix_file_advise()</v> + <v>posix_file_advise() = normal | sequential | random | no_reuse + | will_need | dont_need</v> + <v>Reason = ext_posix()</v> + </type> + <desc> + <p><c>advise/4</c> can be used to announce an intention to access file + data in a specific pattern in the future, thus allowing the + operating system to perform appropriate optimizations.</p> + <p>On some platforms, this function might have no effect.</p> + </desc> + </func> + <func> <name>change_group(Filename, Gid) -> ok | {error, Reason}</name> <fsummary>Change group of a file</fsummary> <type> @@ -584,7 +603,7 @@ f.txt: {person, "kalle", 25}. <type> <v>Filename = name()</v> <v>Modes = [Mode]</v> - <v> Mode = read | write | append | raw | binary | {delayed_write, Size, Delay} | delayed_write | {read_ahead, Size} | read_ahead | compressed</v> + <v> Mode = read | write | append | exclusive | raw | binary | {delayed_write, Size, Delay} | delayed_write | {read_ahead, Size} | read_ahead | compressed</v> <v> Size = Delay = int()</v> <v>IoDevice = io_device()</v> <v>Reason = ext_posix() | system_limit</v> @@ -611,6 +630,17 @@ f.txt: {person, "kalle", 25}. file opened with <c>append</c> will take place at the end of the file.</p> </item> + <tag><c>exclusive</c></tag> + <item> + <p>The file, when opened for writing, is created if it + does not exist. If the file exists, open will return + <c>{error, eexist}</c>.</p> + <warning><p>This option does not guarantee exclusiveness on + file systems that do not support O_EXCL properly, + such as NFS. Do not depend on this option unless you + know that the file system supports it (in general, local + file systems should be safe).</p></warning> + </item> <tag><c>raw</c></tag> <item> <p>The <c>raw</c> option allows faster access to a file, @@ -1641,6 +1671,33 @@ f.txt: {person, "kalle", 25}. </desc> </func> <func> + <name>datasync(IoDevice) -> ok | {error, Reason}</name> + <fsummary>Synchronizes the in-memory data of a file, ignoring most of its metadata, with that on the physical medium</fsummary> + <type> + <v>IoDevice = io_device()</v> + <v>Reason = ext_posix() | terminated</v> + </type> + <desc> + <p>Makes sure that any buffers kept by the operating system + (not by the Erlang runtime system) are written to disk. In + many ways it's resembles fsync but it not requires to update + some of file's metadata such as the access time. On + some platforms, this function might have no effect.</p> + <p>Applications that access databases or log files often write + a tiny data fragment (e.g., one line in a log file) and then + call fsync() immediately in order to ensure that the written + data is physically stored on the harddisk. Unfortunately, fsync() + will always initiate two write operations: one for the newly + written data and another one in order to update the modification + time stored in the inode. If the modification time is not a part + of the transaction concept fdatasync() can be used to avoid + unnecessary inode disk write operations.</p> + <p>Available only in some POSIX systems. This call results in a + call to fsync(), or has no effect, in systems not implementing + the fdatasync syscall.</p> + </desc> + </func> + <func> <name>truncate(IoDevice) -> ok | {error, Reason}</name> <fsummary>Truncate a file</fsummary> <type> |