On Thu, 14 Dec 2023, Martin Frb via fpc-devel wrote:
If I am right the TProcess currently does not allow redirection of StdOut/In
to/from a file (or other handle provided).
If it does, and I have been missing the "how to", then please enlighten me
and disregard the remainder of the mail.
It does not exist out in the open :-)
The code for setting up redirection to pipes (to be read/write by the parent
process) already exists. So this is mainly a call to add properties to
explicitly set those handles.
Or provide some other method.
Is this something that should be added? (I.e. a feature request to be added)
If yes, should there just be 3 properties for the handles? A callback to
create/provide them? A virtual method?
Should there be a flag?
Actually, I already started an implementation of an extension half a year ago.
(although I have the design in mind since several years. Time constraints...)
It's nearly finished, there are still some corner cases that need testing.
The idea is a property of type TIODescriptor (reduced code for readability):
TIOType = (iotNone,iotPipe,iotFIle,iotHandle,iotProcess);
TIODescriptor = class(Tpersistent)
Public
Property Handle : THandle;
Published
property IOType: TIOType;
property FileName : string;
property OnGetHandle : TGetHandleEvent;
property Process : TProcess;
end;
uses as
TProcess = Class()
// ...
Published
Property InputDescriptor : TIODescriptor;
Property OutputDescriptor : TIODescriptor;
Property ErrorDescriptor : TIODescriptor;
end;
What should be the resolving order if handles are give, but other flags
(pipes/input) are set?
Backwards compatibility first and foremost. Setting the poUsePipes option
switches all descriptors to IOType = iotPipe.
I'll see if I can finish the implementation ASAP.
Michael.
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