diff options
Diffstat (limited to 'lib/stdlib/doc/src/io.xml')
| -rw-r--r-- | lib/stdlib/doc/src/io.xml | 222 |
1 files changed, 139 insertions, 83 deletions
diff --git a/lib/stdlib/doc/src/io.xml b/lib/stdlib/doc/src/io.xml index 64fcf4379f..d69e808586 100644 --- a/lib/stdlib/doc/src/io.xml +++ b/lib/stdlib/doc/src/io.xml @@ -4,7 +4,7 @@ <erlref> <header> <copyright> - <year>1996</year><year>2017</year> + <year>1996</year><year>2018</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> @@ -28,7 +28,7 @@ <date></date> <rev></rev> </header> - <module>io</module> + <module since="">io</module> <modulesummary>Standard I/O server interface functions.</modulesummary> <description> <p>This module provides an interface to standard Erlang I/O servers. @@ -104,8 +104,8 @@ <funcs> <func> - <name name="columns" arity="0"/> - <name name="columns" arity="1"/> + <name name="columns" arity="0" since=""/> + <name name="columns" arity="1" since=""/> <fsummary>Get the number of columns of an I/O device.</fsummary> <desc> <p>Retrieves the number of columns of the @@ -116,12 +116,12 @@ </func> <func> - <name name="format" arity="1"/> - <name name="format" arity="2"/> - <name name="format" arity="3"/> - <name name="fwrite" arity="1"/> - <name name="fwrite" arity="2"/> - <name name="fwrite" arity="3"/> + <name name="format" arity="1" since=""/> + <name name="format" arity="2" since=""/> + <name name="format" arity="3" since=""/> + <name name="fwrite" arity="1" since=""/> + <name name="fwrite" arity="2" since=""/> + <name name="fwrite" arity="3" since=""/> <fsummary>Write formatted output.</fsummary> <desc> <p>Writes the items in <c><anno>Data</anno></c> (<c>[]</c>) on the @@ -137,11 +137,11 @@ Hello world! ok</pre> <p>The general format of a control sequence is <c>~F.P.PadModC</c>.</p> - <p>Character <c>C</c> determines the type of control sequence - to be used, <c>F</c> and <c>P</c> are optional numeric - arguments. If <c>F</c>, <c>P</c>, or <c>Pad</c> is <c>*</c>, - the next argument in <c>Data</c> is used as the numeric value - of <c>F</c> or <c>P</c>.</p> + <p>The character <c>C</c> determines the type of control sequence + to be used. It is the only required field. All of <c>F</c>, + <c>P</c>, <c>Pad</c>, and <c>Mod</c> are optional. For example, + to use a <c>#</c> for <c>Pad</c> but use the default values for + <c>F</c> and <c>P</c>, you can write <c>~..#C</c>.</p> <list type="bulleted"> <item> <p><c>F</c> is the <c>field width</c> of the printed argument. A @@ -167,13 +167,26 @@ ok</pre> The default padding character is <c>' '</c> (space).</p> </item> <item> - <p><c>Mod</c> is the control sequence modifier. It is either a - single character (<c>t</c>, for Unicode - translation, and <c>l</c>, for stopping <c>p</c> and - <c>P</c> from detecting printable characters) - that changes the interpretation of <c>Data</c>.</p> + <p><c>Mod</c> is the control sequence modifier. This is + one or more characters that change the interpretation of + <c>Data</c>. The current modifiers are <c>t</c>, for Unicode + translation, and <c>l</c>, for stopping <c>p</c> and <c>P</c> + from detecting printable characters.</p> </item> </list> + <p>If <c>F</c>, <c>P</c>, or <c>Pad</c> is a <c>*</c> character, + the next argument in <c>Data</c> is used as the value. + For example:</p> + <pre> +1> <input>io:fwrite("~*.*.0f~n",[9, 5, 3.14159265]).</input> +003.14159 +ok</pre> + <p>To use a literal <c>*</c> character as <c>Pad</c>, it must be + passed as an argument:</p> + <pre> +2> <input>io:fwrite("~*.*.*f~n",[9, 5, $*, 3.14159265]).</input> +**3.14159 +ok</pre> <p><em>Available control sequences:</em></p> <taglist> <tag><c>~</c></tag> @@ -257,8 +270,9 @@ ok</pre> \x{400} ok 5> <input>io:fwrite("~s~n",[[1024]]).</input> -** exception exit: {badarg,[{io,format,[<0.26.0>,"~s~n",[[1024]]]}, - ...</pre> +** exception error: bad argument + in function io:format/3 + called as io:format(<0.53.0>,"~s~n",[[1024]])</pre> </item> <tag><c>w</c></tag> <item> @@ -276,10 +290,9 @@ ok <c>~w</c>, but breaks terms whose printed representation is longer than one line into many lines and indents each line sensibly. Left-justification is not supported. - It also tries to detect lists of - printable characters and to output these as strings. The - Unicode translation modifier is used for determining - what characters are printable, for example:</p> + It also tries to detect flat lists of + printable characters and output these as strings. + For example:</p> <pre> 1> <input>T = [{attributes,[[{id,age,1.50000},{mode,explicit},</input> <input>{typename,"INTEGER"}], [{id,cho},{mode,explicit},{typename,'Cho'}]]},</input> @@ -301,7 +314,7 @@ ok {mode,implicit}] ok</pre> <p>The field width specifies the maximum line length. - Defaults to 80. The precision specifies the initial + It defaults to 80. The precision specifies the initial indentation of the term. It defaults to the number of characters printed on this line in the <em>same</em> call to <seealso marker="#write/1"><c>write/1</c></seealso> or @@ -319,11 +332,22 @@ Here T = [{attributes,[[{id,age,1.5}, {tag,{'PRIVATE',3}}, {mode,implicit}] ok</pre> + + <p>As from Erlang/OTP 21.0, a field width of value + <c>0</c> can be used for specifying that a line is + infinitely long, which means that no line breaks + are inserted. For example:</p> + + <pre> +5> <input>io:fwrite("~0p~n", [lists:seq(1, 30)]).</input> +[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30] +ok</pre> + <p>When the modifier <c>l</c> is specified, no detection of printable character lists takes place, for example:</p> <pre> -5> <input>S = [{a,"a"}, {b, "b"}].</input> -6> <input>io:fwrite("~15p~n", [S]).</input> +6> <input>S = [{a,"a"}, {b, "b"}], + io:fwrite("~15p~n", [S]).</input> [{a,"a"}, {b,"b"}] ok @@ -331,18 +355,53 @@ ok [{a,[97]}, {b,[98]}] ok</pre> - <p>Binaries that look like UTF-8 encoded strings are - output with the string syntax if the Unicode translation - modifier is specified:</p> + <p>The Unicode translation modifier <c>t</c> specifies how to treat + characters outside the Latin-1 range of codepoints, in + atoms, strings, and binaries. For example, printing an atom + containing a character > 255:</p> + <pre> +8> <input>io:fwrite("~p~n",[list_to_atom([1024])]).</input> +'\x{400}' +ok +9> <input>io:fwrite("~tp~n",[list_to_atom([1024])]).</input> +'Ѐ' +ok</pre> + <p>By default, Erlang only detects lists of characters + in the Latin-1 range as strings, but the <c>+pc unicode</c> + flag can be used to change this (see <seealso + marker="#printable_range/0"> + <c>printable_range/0</c></seealso> for details). For example:</p> <pre> -9> <input>io:fwrite("~p~n",[[1024]]).</input> +10> <input>io:fwrite("~p~n",[[214]]).</input> +"Ö" +ok +11> <input>io:fwrite("~p~n",[[1024]]).</input> +[1024] +ok +12> <input>io:fwrite("~tp~n",[[1024]]).</input> +[1024] +ok +</pre> + <p>but if Erlang was started with <c>+pc unicode</c>:</p> + <pre> +13> <input>io:fwrite("~p~n",[[1024]]).</input> [1024] -10> <input>io:fwrite("~tp~n",[[1024]]).</input> -"\x{400}" -11> <input>io:fwrite("~tp~n", [<<128,128>>]).</input> +ok +14> <input>io:fwrite("~tp~n",[[1024]]).</input> +"Ѐ" +ok</pre> + <p>Similarly, binaries that look like UTF-8 encoded strings + are output with the binary string syntax if the <c>t</c> + modifier is specified:</p> + <pre> +15> <input>io:fwrite("~p~n", [<<208,128>>]).</input> +<<208,128>> +ok +16> <input>io:fwrite("~tp~n", [<<208,128>>]).</input> +<<"Ѐ"/utf8>> +ok +17> <input>io:fwrite("~tp~n", [<<128,128>>]).</input> <<128,128>> -12> <input>io:fwrite("~tp~n", [<<208,128>>]).</input> -<<"\x{400}"/utf8>> ok</pre> </item> <tag><c>W</c></tag> @@ -454,12 +513,9 @@ ok</pre> abc def 'abc def' {foo,1} A ok 2> <input>io:fwrite("~s", [65]).</input> -** exception exit: {badarg,[{io,format,[<0.22.0>,"~s","A"]}, - {erl_eval,do_apply,5}, - {shell,exprs,6}, - {shell,eval_exprs,6}, - {shell,eval_loop,3}]} - in function io:o_request/2</pre> +** exception error: bad argument + in function io:format/3 + called as io:format(<0.53.0>,"~s","A")</pre> <p>In this example, an attempt was made to output the single character 65 with the aid of the string formatting directive <c>"~s"</c>.</p> @@ -467,8 +523,8 @@ ok </func> <func> - <name name="fread" arity="2"/> - <name name="fread" arity="3"/> + <name name="fread" arity="2" since=""/> + <name name="fread" arity="3" since=""/> <fsummary>Read formatted input.</fsummary> <type name="server_no_data"/> <desc> @@ -634,8 +690,8 @@ enter><input>:</input> <input>alan</input> <input>:</input> <input>joe</in </func> <func> - <name name="get_chars" arity="2"/> - <name name="get_chars" arity="3"/> + <name name="get_chars" arity="2" since=""/> + <name name="get_chars" arity="3" since=""/> <fsummary>Read a specified number of characters.</fsummary> <type name="server_no_data"/> <desc> @@ -666,8 +722,8 @@ enter><input>:</input> <input>alan</input> <input>:</input> <input>joe</in </func> <func> - <name name="get_line" arity="1"/> - <name name="get_line" arity="2"/> + <name name="get_line" arity="1" since=""/> + <name name="get_line" arity="2" since=""/> <fsummary>Read a line.</fsummary> <type name="server_no_data"/> <desc> @@ -698,8 +754,8 @@ enter><input>:</input> <input>alan</input> <input>:</input> <input>joe</in </func> <func> - <name name="getopts" arity="0"/> - <name name="getopts" arity="1"/> + <name name="getopts" arity="0" since=""/> + <name name="getopts" arity="1" since=""/> <fsummary>Get the supported options and values from an I/O server. </fsummary> <desc> @@ -725,8 +781,8 @@ enter><input>:</input> <input>alan</input> <input>:</input> <input>joe</in </func> <func> - <name name="nl" arity="0"/> - <name name="nl" arity="1"/> + <name name="nl" arity="0" since=""/> + <name name="nl" arity="1" since=""/> <fsummary>Write a newline.</fsummary> <desc> <p>Writes new line to the standard output @@ -735,10 +791,10 @@ enter><input>:</input> <input>alan</input> <input>:</input> <input>joe</in </func> <func> - <name name="parse_erl_exprs" arity="1"/> - <name name="parse_erl_exprs" arity="2"/> - <name name="parse_erl_exprs" arity="3"/> - <name name="parse_erl_exprs" arity="4"/> + <name name="parse_erl_exprs" arity="1" since=""/> + <name name="parse_erl_exprs" arity="2" since=""/> + <name name="parse_erl_exprs" arity="3" since=""/> + <name name="parse_erl_exprs" arity="4" since="OTP R16B"/> <fsummary>Read, tokenize, and parse Erlang expressions.</fsummary> <type name="parse_ret"/> <type name="server_no_data"/> @@ -788,10 +844,10 @@ enter><input>abc("hey".</input> </func> <func> - <name name="parse_erl_form" arity="1"/> - <name name="parse_erl_form" arity="2"/> - <name name="parse_erl_form" arity="3"/> - <name name="parse_erl_form" arity="4"/> + <name name="parse_erl_form" arity="1" since=""/> + <name name="parse_erl_form" arity="2" since=""/> + <name name="parse_erl_form" arity="3" since=""/> + <name name="parse_erl_form" arity="4" since="OTP R16B"/> <fsummary>Read, tokenize, and parse an Erlang form.</fsummary> <type name="parse_form_ret"/> <type name="server_no_data"/> @@ -832,7 +888,7 @@ enter><input>abc("hey".</input> </func> <func> - <name name="printable_range" arity="0"/> + <name name="printable_range" arity="0" since="OTP R16B"/> <fsummary>Get user-requested printable character range.</fsummary> <desc> <p>Returns the user-requested range of printable Unicode characters.</p> @@ -862,8 +918,8 @@ enter><input>abc("hey".</input> </func> <func> - <name name="put_chars" arity="1"/> - <name name="put_chars" arity="2"/> + <name name="put_chars" arity="1" since=""/> + <name name="put_chars" arity="2" since=""/> <fsummary>Write a list of characters.</fsummary> <desc> <p>Writes the characters of <c><anno>CharData</anno></c> to the I/O @@ -872,8 +928,8 @@ enter><input>abc("hey".</input> </func> <func> - <name name="read" arity="1"/> - <name name="read" arity="2"/> + <name name="read" arity="1" since=""/> + <name name="read" arity="2" since=""/> <fsummary>Read a term.</fsummary> <type name="server_no_data"/> <desc> @@ -904,8 +960,8 @@ enter><input>abc("hey".</input> </func> <func> - <name name="read" arity="3"/> - <name name="read" arity="4"/> + <name name="read" arity="3" since=""/> + <name name="read" arity="4" since="OTP R16B"/> <fsummary>Read a term.</fsummary> <type name="server_no_data"/> <desc> @@ -941,8 +997,8 @@ enter><input>abc("hey".</input> </func> <func> - <name name="rows" arity="0"/> - <name name="rows" arity="1"/> + <name name="rows" arity="0" since=""/> + <name name="rows" arity="1" since=""/> <fsummary>Get the number of rows of an I/O device.</fsummary> <desc> <p>Retrieves the number of rows of <c><anno>IoDevice</anno></c> @@ -953,10 +1009,10 @@ enter><input>abc("hey".</input> </func> <func> - <name name="scan_erl_exprs" arity="1"/> - <name name="scan_erl_exprs" arity="2"/> - <name name="scan_erl_exprs" arity="3"/> - <name name="scan_erl_exprs" arity="4"/> + <name name="scan_erl_exprs" arity="1" since=""/> + <name name="scan_erl_exprs" arity="2" since=""/> + <name name="scan_erl_exprs" arity="3" since=""/> + <name name="scan_erl_exprs" arity="4" since="OTP R16B"/> <fsummary>Read and tokenize Erlang expressions.</fsummary> <type name="server_no_data"/> <desc> @@ -1004,10 +1060,10 @@ enter><input>1.0er.</input> </func> <func> - <name name="scan_erl_form" arity="1"/> - <name name="scan_erl_form" arity="2"/> - <name name="scan_erl_form" arity="3"/> - <name name="scan_erl_form" arity="4"/> + <name name="scan_erl_form" arity="1" since=""/> + <name name="scan_erl_form" arity="2" since=""/> + <name name="scan_erl_form" arity="3" since=""/> + <name name="scan_erl_form" arity="4" since="OTP R16B"/> <fsummary>Read and tokenize an Erlang form.</fsummary> <type name="server_no_data"/> <desc> @@ -1027,8 +1083,8 @@ enter><input>1.0er.</input> </func> <func> - <name name="setopts" arity="1"/> - <name name="setopts" arity="2"/> + <name name="setopts" arity="1" since=""/> + <name name="setopts" arity="2" since=""/> <fsummary>Set options.</fsummary> <desc> <p>Set options for the standard I/O device @@ -1142,8 +1198,8 @@ fun("") -> {yes, "quit", []}; </func> <func> - <name name="write" arity="1"/> - <name name="write" arity="2"/> + <name name="write" arity="1" since=""/> + <name name="write" arity="2" since=""/> <fsummary>Write a term.</fsummary> <desc> <p>Writes term <c><anno>Term</anno></c> to the standard output |