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-rw-r--r--system/doc/reference_manual/typespec.xml15
-rw-r--r--system/doc/tutorial/c_port.xmlsrc4
2 files changed, 11 insertions, 8 deletions
diff --git a/system/doc/reference_manual/typespec.xml b/system/doc/reference_manual/typespec.xml
index 1899efd5f3..ced584ed35 100644
--- a/system/doc/reference_manual/typespec.xml
+++ b/system/doc/reference_manual/typespec.xml
@@ -409,11 +409,13 @@
The initial values for fields are to be compatible
with (that is, a member of) the corresponding types.
This is checked by the compiler and results in a compilation error
- if a violation is detected. For fields without initial values,
- the singleton type <c>'undefined'</c> is added to all declared types.
- In other words, the following two record declarations have identical
- effects:
+ if a violation is detected.
</p>
+ <note>
+ <p>Before Erlang/OTP 19, for fields without initial values,
+ the singleton type <c>'undefined'</c> was added to all declared types.
+ In other words, the following two record declarations had identical
+ effects:</p>
<pre>
-record(rec, {f1 = 42 :: integer(),
f2 :: float(),
@@ -423,9 +425,10 @@
f2 :: 'undefined' | float(),
f3 :: 'undefined' | 'a' | 'b'}).</pre>
<p>
- For this reason, it is recommended that records contain initializers,
- whenever possible.
+ This is no longer the case. If you require <c>'undefined'</c> in your record field
+ type, you must explicitly add it to the typespec, as in the 2nd example.
</p>
+ </note>
<p>
Any record, containing type information or not, once defined,
can be used as a type using the following syntax:
diff --git a/system/doc/tutorial/c_port.xmlsrc b/system/doc/tutorial/c_port.xmlsrc
index 695f16515d..3c3bc48044 100644
--- a/system/doc/tutorial/c_port.xmlsrc
+++ b/system/doc/tutorial/c_port.xmlsrc
@@ -98,11 +98,11 @@ loop(Port) ->
{call, Caller, Msg} ->
Port ! {self(), {command, encode(Msg)}},
receive
- {Port, {data, Data}} ->
+ {Port, {data, Data}} ->
Caller ! {complex, decode(Data)}
end,
loop(Port)
- end.</pre>
+ end.</pre>
<p>Assuming that both the arguments and the results from the C
functions are less than 256, a simple encoding/decoding scheme
is employed. In this scheme, <c>foo</c> is represented by byte