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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 /erts/preloaded/src | |
| 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 'erts/preloaded/src')
| -rw-r--r-- | erts/preloaded/src/prim_file.erl | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/erts/preloaded/src/prim_file.erl b/erts/preloaded/src/prim_file.erl index 2d177bf80e..7f24889bb2 100644 --- a/erts/preloaded/src/prim_file.erl +++ b/erts/preloaded/src/prim_file.erl @@ -116,9 +116,10 @@ -define(EFILE_MODE_READ_WRITE, 3). -define(EFILE_MODE_APPEND, 4). -define(EFILE_COMPRESSED, 8). +-define(EFILE_MODE_EXCL, 16). %% Use this mask to get just the mode bits to be passed to the driver. --define(EFILE_MODE_MASK, 15). +-define(EFILE_MODE_MASK, 31). %% Seek modes for the driver's seek function. -define(EFILE_SEEK_SET, 0). @@ -958,6 +959,8 @@ open_mode([compressed|Rest], Mode, Portopts, Setopts) -> open_mode([append|Rest], Mode, Portopts, Setopts) -> open_mode(Rest, Mode bor ?EFILE_MODE_APPEND bor ?EFILE_MODE_WRITE, Portopts, Setopts); +open_mode([exclusive|Rest], Mode, Portopts, Setopts) -> + open_mode(Rest, Mode bor ?EFILE_MODE_EXCL, Portopts, Setopts); open_mode([delayed_write|Rest], Mode, Portopts, Setopts) -> open_mode([{delayed_write, 64*1024, 2000}|Rest], Mode, Portopts, Setopts); |