Accessing bi-directional parallel port w/C

Accessing bi-directional parallel port w/C

Post by Sue Gleeso » Wed, 11 Sep 1996 04:00:00



Hi Folks,

Hopefully someone out there can help me.  I've exhausted all the
resources I can find on my own.

I'm attempting to read and write the bi-directional parallel port on
Solaris 2.5 - specifically, /dev/bpp0.  

I'm having 2 problems:  

        1.  I can't seem to get data off the port using read(),
            even though there is data to be read.  read() always
            returns 0.

        2.  I can't get either select() or poll() to work with this
            device.  They both return -1, with errno set to ENXIO.
            ENXIO doesn't make sense, as the open() for the device
            worked just fine, and I *am* able to write() successfully.

Does anyone have any thoughts on what's going on?  I get the select()/
poll() problem on Digital UNIX V4.0 as well, so it sounds as though I
have something more fundamentally wrong with my approach.

Any/all suggestions/comments welcome.  Mail is also welcome at

Thanks,

Sue Gleeson

 
 
 

1. Accessing bi-directional parallel port w/C

Hi Folks,

Hopefully someone out there can help me.  I've exhausted all the
resources I can find on my own.

I'm attempting to read and write the bi-directional parallel port on
Solaris 2.5 - specifically, /dev/bpp0.  

I'm having 2 problems:  

        1.  I can't seem to get data off the port using read(),
            even though there is data to be read.  read() always
            returns 0.

        2.  I can't get either select() or poll() to work with this
            device.  They both return -1, with errno set to ENXIO.
            ENXIO doesn't make sense, as the open() for the device
            worked just fine, and I *am* able to write() successfully.

Does anyone have any thoughts on what's going on?  I get the select()/
poll() problem on Digital UNIX V4.0 as well, so it sounds as though I
have something more fundamentally wrong with my approach.

Any/all suggestions/comments welcome.  Mail is also welcome at

Thanks,

Sue Gleeson

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