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How to write to stdin of another program (program A -> [stdin]program B)

 
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Old 04-30-2008
How to write to stdin of another program (program A -> [stdin]program B)
Hi,
Program A: uses pipe()

I am able to read the stdout of PROGAM B (stdout got through system() command) into PROGRAM A using:

* child
-> dup2(fd[1], STDOUT_FILENO);
-> execl("/path/PROGRAM B", "PROGRAM B", NULL);

* parent
-> char line[100];
-> read(fd[0], line, 100);


Question:
---------
How to write to stdin of PROGRAM B from PROGRAM A?
* should I use a different pipe?
* how to I read stdin in PROGRAM B? using cin?

Thanks in advance,
Vivek
 
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LEARN ABOUT DEBIAN

gpiv_getbit

GPIV_GETBIT(1)						      General Commands Manual						    GPIV_GETBIT(1)

NAME

       gpiv_getbit - Image processing program for PIV images.

SYNOPSIS

       gpiv_getbit [-b N] [-h | --help] [-p | --print] [-v | --version] [filename] < stdin > stdout

DESCRIPTION

       gpiv_getbit  get the N least significant bits and moves them to most the significant bits. This results that a weak image signal (pixels of
       low value) is amplified while the high signal within the image will be removed.

       The parameters read from the configuration resources (containing the key GPIV_IMGPROC) may be overruled by the  command	line  options,	as
       explained below.

Options
       -b N   Defines the bit number [0, .., 7]. Signal from 0 to N will be shifted.

       -h | --help
	      On-line help

       -v | --version
	      Print version information on standard output, then exit successfully.

       filename
	      Input image filename. Overrides stdin and stdout with the full filename of the image. Output will be written to filename.png. Param-
	      eters are stored in filename.par and may be used for future use by including them in ./gpivrc. If stdin and  stdout  are	used,  the
	      input is expected to be a PNG formatted image.

       SEE ALSO
	      gpivtools

AUTHOR

       Gerber Van der Graaf

								  7 November 2006						    GPIV_GETBIT(1)