This isn't really a xforms questions,but it occured during xforms app
development...
I am working on a xforms mp3 player... I am using mpg123 as the actual
player, forking it from the app. No problem....
There is a version of mpg123 for interactive use called mpg123m. It is
included with the tk3play app. mpg123m not only accepts futher commands
while it is playing, it also gives progress, play time, blocks played,
etc, will it is running.
tk3play uses it's pipes to send and get data. No problem I thought. Just
use pipes in C.
Big problems, at least to me....
Pipes don't work like I thought.....
I set up a command line test app to spawn mpg123 and take further
commands from inut lines and send it to the mpg123m child . No problem.
I start my app which spawns mpg123m. I then enter 2 0mp3/cobramp3 ( the
command mpg123 expects to begin playing a file) which is read by my app
and sent through outPipe[1] to mpg123m. It starts playing and it's
progress output comes to the screen.
I then add the pipe for the output of the child (mpg123m) to come back
to the parent...NO GO......
I try a test app and child to get better aquainted with pipes...
I find that if the child wants to send back it HAS to use a write() and
not puts() or printf().
I find that if the parent writes out pipe[0], it is echoed back to
pipe[1].
How do you overcome these problems.
How do you turn off the echo between pipes[0] and pipes[1] at the
parent????
Why is the child not piping back to the parent when it uses puts() or
printf()??? This means that you cannot get the output of an app piped
back unless that app dows not use puts()'s and printf()'s.... How can
tht be quarantied????
I understand that printf() uses streams (FILE *) while write() uses file
descriptors(integers). But, I thought that printfputs mapped to
STDOUT_FILENO....
-- Jeff Pierce piercej@preferred.com _________________________________________________ To unsubscribe, send the message "unsubscribe" to xforms-request@bob.usuhs.mil or see http://bob.usuhs.mil/mailserv/xforms.html XForms Home Page: http://bragg.phys.uwm.edu/xforms List Archive: http://bob.usuhs.mil/mailserv/list-archives/