diff options
Diffstat (limited to 'lib/kernel/doc/src/file.xml')
| -rw-r--r-- | lib/kernel/doc/src/file.xml | 134 |
1 files changed, 103 insertions, 31 deletions
diff --git a/lib/kernel/doc/src/file.xml b/lib/kernel/doc/src/file.xml index 861c582211..772eff13cc 100644 --- a/lib/kernel/doc/src/file.xml +++ b/lib/kernel/doc/src/file.xml @@ -60,11 +60,13 @@ converted, why the Unicode mode for file names is not default on systems having completely transparent file naming.</p> - <note>As of R14B01, the most basic file handling modules - (<c>file</c>, <c>prim_file</c>, <c>filelib</c> and - <c>filename</c>) accept raw file names, but the rest of OTP is not - guaranteed to handle them, why Unicode file naming on systems - where it is not default is still considered experimental.</note> + <note> + <p>As of R14B01, the most basic file handling modules + (<c>file</c>, <c>prim_file</c>, <c>filelib</c> and + <c>filename</c>) accept raw file names, but the rest of OTP is not + guaranteed to handle them, why Unicode file naming on systems + where it is not default is still considered experimental.</p> + </note> <p>Raw file names is a new feature in OTP R14B01, which allows the user to supply completely uninterpreted file names to the @@ -147,6 +149,12 @@ <datatype> <name name="mode"/> </datatype> + <datatype> + <name name="file_info_option"/> + </datatype> + <datatype> + <name name="sendfile_option"/> + </datatype> </datatypes> <funcs> @@ -249,11 +257,9 @@ </item> </taglist> <p>Example:</p> - <code type="none"> -f.txt: {person, "kalle", 25}. +<code type="none">f.txt: {person, "kalle", 25}. {person, "pelle", 30}.</code> - <pre> -1> <input>file:consult("f.txt").</input> +<pre>1> <input>file:consult("f.txt").</input> {ok,[{person,"kalle",25},{person,"pelle",30}]}</pre> </desc> </func> @@ -362,7 +368,6 @@ f.txt: {person, "kalle", 25}. <p>In a future release, a bad type for the <c><anno>Filename</anno></c> argument will probably generate an exception.</p> - <p></p> </warning> </desc> </func> @@ -410,7 +415,7 @@ f.txt: {person, "kalle", 25}. <name>file_info(Filename) -> {ok, FileInfo} | {error, Reason}</name> <fsummary>Get information about a file (deprecated)</fsummary> <desc> - <p>This function is obsolete. Use <c>read_file_info/1</c> + <p>This function is obsolete. Use <c>read_file_info/1,2</c> instead.</p> </desc> </func> @@ -537,7 +542,7 @@ f.txt: {person, "kalle", 25}. <desc> <p>Makes a hard link from <c><anno>Existing</anno></c> to <c><anno>New</anno></c>, on - platforms that support links (Unix). This function returns + platforms that support links (Unix and Windows). This function returns <c>ok</c> if the link was successfully created, or <c>{error, <anno>Reason</anno>}</c>. On platforms that do not support links, <c>{error,enotsup}</c> is returned.</p> @@ -564,11 +569,12 @@ f.txt: {person, "kalle", 25}. <name name="make_symlink" arity="2"/> <fsummary>Make a symbolic link to a file or directory</fsummary> <desc> - <p>This function creates a symbolic link <c><anno>Name2</anno></c> to - the file or directory <c><anno>Name1</anno></c>, on platforms that - support - symbolic links (most Unix systems). <c><anno>Name1</anno></c> need not - exist. This function returns <c>ok</c> if the link was + <p>This function creates a symbolic link <c><anno>New</anno></c> to + the file or directory <c><anno>Existing</anno></c>, on platforms that + support symbolic links (most Unix systems and Windows beginning with + Vista). + <c><anno>Existing</anno></c> need not exist. + This function returns <c>ok</c> if the link was successfully created, or <c>{error, <anno>Reason</anno>}</c>. On platforms that do not support symbolic links, <c>{error, enotsup}</c> @@ -578,11 +584,11 @@ f.txt: {person, "kalle", 25}. <tag><c>eacces</c></tag> <item> <p>Missing read or write permissions for the parent directories - of <c><anno>Name1</anno></c> or <c><anno>Name2</anno></c>.</p> + of <c><anno>Existing</anno></c> or <c><anno>New</anno></c>.</p> </item> <tag><c>eexist</c></tag> <item> - <p><c><anno>Name2</anno></c> already exists.</p> + <p><c><anno>New</anno></c> already exists.</p> </item> <tag><c>enotsup</c></tag> <item> @@ -1186,6 +1192,7 @@ f.txt: {person, "kalle", 25}. </func> <func> <name name="read_file_info" arity="1"/> + <name name="read_file_info" arity="2"/> <fsummary>Get information about a file</fsummary> <desc> <p>Retrieves information about a file. Returns @@ -1197,6 +1204,20 @@ f.txt: {person, "kalle", 25}. from which the function is called:</p> <code type="none"> -include_lib("kernel/include/file.hrl").</code> + <p>The time type returned in <c>atime</c>, <c>mtime</c> and <c>ctime</c> + is dependent on the time type set in <c>Opts :: {time, Type}</c>. + Type <c>local</c> will return local time, <c>universal</c> will + return universal time and <c>posix</c> will return seconds since + or before unix time epoch which is 1970-01-01 00:00 UTC. + Default is <c>{time, local}</c>. + </p> + <note> + <p> + Since file times is stored in posix time on most OS it is + faster to query file information with the <c>posix</c> option. + </p> + </note> + <p>The record <c>file_info</c> contains the following fields.</p> <taglist> <tag><c>size = integer()</c></tag> @@ -1211,15 +1232,15 @@ f.txt: {person, "kalle", 25}. <item> <p>The current system access to the file.</p> </item> - <tag><c>atime = <seealso marker="#type-date_time">date_time()</seealso></c></tag> + <tag><c>atime = <seealso marker="#type-date_time">date_time()</seealso> | integer() </c></tag> <item> - <p>The last (local) time the file was read.</p> + <p>The last time the file was read.</p> </item> - <tag><c>mtime = <seealso marker="#type-date_time">date_time()</seealso></c></tag> + <tag><c>mtime = <seealso marker="#type-date_time">date_time()</seealso> | integer() </c></tag> <item> - <p>The last (local) time the file was written.</p> + <p>The last time the file was written.</p> </item> - <tag><c>ctime = <seealso marker="#type-date_time">date_time()</seealso></c></tag> + <tag><c>ctime = <seealso marker="#type-date_time">date_time()</seealso> | integer() </c></tag> <item> <p>The interpretation of this time field depends on the operating system. On Unix, it is the last time @@ -1375,9 +1396,11 @@ f.txt: {person, "kalle", 25}. </func> <func> <name name="read_link_info" arity="1"/> + <name name="read_link_info" arity="2"/> <fsummary>Get information about a link or file</fsummary> <desc> - <p>This function works like <c>read_file_info/1</c>, except that + <p>This function works like + <seealso marker="#read_file_info/2">read_file_info/1,2</seealso> except that if <c><anno>Name</anno></c> is a symbolic link, information about the link will be returned in the <c>file_info</c> record and the <c>type</c> field of the record will be set to @@ -1523,7 +1546,6 @@ f.txt: {person, "kalle", 25}. <p>In a future release, a bad type for the <c><anno>Dir</anno></c> argument will probably generate an exception.</p> - <p></p> </warning> </desc> </func> @@ -1576,6 +1598,48 @@ f.txt: {person, "kalle", 25}. </desc> </func> <func> + <name name="sendfile" arity="2"/> + <fsummary>send a file to a socket</fsummary> + <desc> + <p>Sends the file <c>Filename</c> to <c>Socket</c>. + Returns <c>{ok, BytesSent}</c> if successful, + otherwise <c>{error, Reason}</c>.</p> + </desc> + </func> + <func> + <name name="sendfile" arity="5"/> + <fsummary>send a file to a socket</fsummary> + <desc> + <p>Sends <c>Bytes</c> from the file + referenced by <c>RawFile</c> beginning at <c>Offset</c> to + <c>Socket</c>. + Returns <c>{ok, BytesSent}</c> if successful, + otherwise <c>{error, Reason}</c>. If <c>Bytes</c> is set to + 0 all data after the given <c>Offset</c> is sent.</p> + <p>The file used must be opened using the raw flag, and the process + calling sendfile must be the controlling process of the socket. + See <seealso marker="gen_tcp#controlling_process-2">gen_tcp:controlling_process/2</seealso></p> + <p>If the OS used does not support sendfile, an Erlang fallback + using file:read and gen_tcp:send is used.</p> + <p>The option list can contain the following options: + <taglist> + <tag><c>chunk_size</c></tag> + <item>The chunk size used by the erlang fallback to send + data. If using the fallback, this should be set to a value + which comfortably fits in the systems memory. Default is 20 MB.</item> + </taglist> + </p> + <p>On operating systems with thread support, it is recommended to use + async threads. See the command line flag + <c>+A</c> in <seealso marker="erts:erl">erl(1)</seealso>. If it is not + possible to use async threads for sendfile, it is recommended to use + a relatively small value for the send buffer on the socket. Otherwise + the Erlang VM might loose some of its soft realtime guarantees. + Which size to use depends on the OS/hardware and the requirements + of the application.</p> + </desc> + </func> + <func> <name name="write" arity="2"/> <fsummary>Write to a file</fsummary> <desc> @@ -1647,6 +1711,7 @@ f.txt: {person, "kalle", 25}. </func> <func> <name name="write_file_info" arity="2"/> + <name name="write_file_info" arity="3"/> <fsummary>Change information about a file</fsummary> <desc> <p>Change file information. Returns <c>ok</c> if successful, @@ -1657,18 +1722,25 @@ f.txt: {person, "kalle", 25}. from which the function is called:</p> <code type="none"> -include_lib("kernel/include/file.hrl").</code> + <p>The time type set in <c>atime</c>, <c>mtime</c> and <c>ctime</c> + is dependent on the time type set in <c>Opts :: {time, Type}</c>. + Type <c>local</c> will interpret the time set as local, <c>universal</c> will + interpret it as universal time and <c>posix</c> must be seconds since + or before unix time epoch which is 1970-01-01 00:00 UTC. + Default is <c>{time, local}</c>. + </p> <p>The following fields are used from the record, if they are given.</p> <taglist> - <tag><c>atime = <seealso marker="#type-date_time">date_time()</seealso></c></tag> + <tag><c>atime = <seealso marker="#type-date_time">date_time()</seealso> | integer()</c></tag> <item> - <p>The last (local) time the file was read.</p> + <p>The last time the file was read.</p> </item> - <tag><c>mtime = <seealso marker="#type-date_time">date_time()</seealso></c></tag> + <tag><c>mtime = <seealso marker="#type-date_time">date_time()</seealso> | integer()</c></tag> <item> - <p>The last (local) time the file was written.</p> + <p>The last time the file was written.</p> </item> - <tag><c>ctime = <seealso marker="#type-date_time">date_time()</seealso></c></tag> + <tag><c>ctime = <seealso marker="#type-date_time">date_time()</seealso> | integer()</c></tag> <item> <p>On Unix, any value give for this field will be ignored (the "ctime" for the file will be set to the current |