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| author | Michael Santos <[email protected]> | 2010-04-30 12:22:11 -0400 |
|---|---|---|
| committer | Raimo Niskanen <[email protected]> | 2010-06-04 10:47:56 +0200 |
| commit | 4bd026cccb2c22279dd9c88e704642c5a65d3c53 (patch) | |
| tree | 5c801bf9813b575eb302039f78b07b50364b6696 /lib/kernel/doc | |
| parent | cbd1378ee1fde835e55614bac9290b281bafe49a (diff) | |
| download | otp-4bd026cccb2c22279dd9c88e704642c5a65d3c53.tar.gz otp-4bd026cccb2c22279dd9c88e704642c5a65d3c53.tar.bz2 otp-4bd026cccb2c22279dd9c88e704642c5a65d3c53.zip | |
Support opening files in exclusive mode
Add an option that atomically tests for the existence of a file and
creates it if the file does not exist, by passing the O_EXCL flag
to open() on Unix and CREATE_NEW flag on Windows. Support for O_EXCL
varies across platforms and filesystems.
{ok, Fd} = file:open("/tmp/foo", [write,exclusive]),
{error, eexist} = file:open("/tmp/foo", [write,exclusive]).
Diffstat (limited to 'lib/kernel/doc')
| -rw-r--r-- | lib/kernel/doc/src/file.xml | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/lib/kernel/doc/src/file.xml b/lib/kernel/doc/src/file.xml index 382262d1ee..a9ceac0bcf 100644 --- a/lib/kernel/doc/src/file.xml +++ b/lib/kernel/doc/src/file.xml @@ -603,7 +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> @@ -630,6 +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, |