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Re: Can one close only one of STDIN and STDOUT when using SPAWN with the UNIT keyword? [message #83716 is a reply to message #83700]

Wed, 27 March 2013 06:27

bstecklu
Messages: 14
Registered: February 2012

Junior Member

Tom Grydeland wrote:
> Hi all,
>
> Some commands only produce output after all of the input has been consumed.
> For such a command, the usual approach when given input and output streams is
> to open both, feed the process all its input, close the input stream and then
> read the result on the output stream.
>
> In IDL, when using SPAWN with the UNIT keyword, one file unit is supposed to
> be used for both directions. Is it possible to do the above from IDL?
>
> For example, if the external command is a checksum program, like 'md5sum':
>
> IDL> SPAWN, 'md5sum', UNIT=unit
> IDL> WRITEU, unit, 'foo'
> IDL> {close unit in the input-to-md5sum direction}
> IDL> READU, unit, checksum
> IDL> {proceed with checksum}
>
> Can the above be done from IDL? How?
>
> --T (tom.grydeland@norut.no)

May be I am missing your point but

IDL> WRITEU, unit, 'foo' & SPAWN, 'md5sum foo', checksum

will give you the result in the string (array) checksum.

Bringfried

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[Message index]

		Re: Can one close only one of STDIN and STDOUT when using SPAWN with the UNIT keyword? By: Craig Markwardt on Wed, 27 March 2013 12:02
		Re: Can one close only one of STDIN and STDOUT when using SPAWN with the UNIT keyword? By: bstecklu on Wed, 27 March 2013 06:27
		Re: Can one close only one of STDIN and STDOUT when using SPAWN with the UNIT keyword? By: tom.grydeland on Sun, 31 March 2013 02:35

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