在持久性程序功能中打开STREAM [英] Opening a STREAM in a Persistent Procedure Function

问题描述

我有一个持久性过程，我试图在其中打开，写入和关闭流.

I have a persistent procedure, in which I am trying to open, write and close a stream.

我在程序的主要区域

DEFINE STREAM sOutFile.
OPEN STREAM sOutFile TO VALUE( outFileName ).
MESSAGE SEEK( sOutFile ).

，然后是持久性过程中的功能

and subsequently a function within the persistent procedure

FUNCTION example RETURN LOGICAL:
  MESSAGE SEEK( sOutFile ).
  PUT STREAM sOutFile UNFORMATTED someData.
END.

实例化持久性过程时，消息显示为"0"，因此流已打开.但是，在调用example时，消息显示为?"并收到一条有关尝试写入封闭流的消息.

When the persistent procedure is instantiated, the message displays "0" so the stream has been opened. However, when example is called, the message displays "?" and I get a message about attempting to write to a closed stream.

我尝试声明流为"NEW SHARED"(新共享)，但这没有任何区别.

I've tried declaring the stream NEW SHARED but that didn't make any difference.

我做错什么了吗，还是不可能在持久性过程中定义流?

Am I doing something wrong, or is it impossible to define streams within persistent procedures?

推荐答案

现在还很早，我的咖啡还没有加入，但是我认为您必须在PP体外打开水流.

It is early and my coffee hasn't kicked in yet but I think that you have to open the stream outside the body of the PP.

这有效:

/* ppstream.p
 *
 */

define stream logStream.

session:add-super-procedure( this-procedure ).

/* end of PP init */

function initLog returns logical ( input lgFile as character ):
  output stream logStream to value( lgFile ) unbuffered.
  return true.
end.

function logStuff returns logical ( input msg as character ):
  put stream logStream unformatted msg skip.
  return true.
end.

，然后这样称呼它:

function initLog  returns logical ( input lgFile as character ) in super.
function logStuff returns logical ( input msg as character ) in super.

run ./ppstream.p persistent.

initLog( "log.txt" ).
logStuff( "test" ).

(我使用了会话超级过程来避免必须定义句柄-您不一定需要这样做.)

(I used a session super-procedure to avoid having to define handles -- you would not necessarily need to do that.)

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