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-rw-r--r--lib/stdlib/doc/src/io.xml33
1 files changed, 23 insertions, 10 deletions
diff --git a/lib/stdlib/doc/src/io.xml b/lib/stdlib/doc/src/io.xml
index 6a7c06188b..f1037ec76b 100644
--- a/lib/stdlib/doc/src/io.xml
+++ b/lib/stdlib/doc/src/io.xml
@@ -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 a
- single character that changes the interpretation of
- <c>Data</c>. This can be <c>t</c>, for Unicode translation,
- or <c>l</c>, for stopping <c>p</c> and <c>P</c> from
- detecting printable characters.</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>