OpenEuphoria

2. Re: Pipe Input/Output

• Posted by jimcbrown (admin) Apr 05, 2014
• 1955 views

Yes, that's the whole point of the library. It's a platform-independent way of launching and communicating with processes.

Take a look at pipes.ex/pipe_sub.ex in demos for an example.

Basically, you create a pipe with pipeio:create(), then you launch the process with pipeio:exec("command line here", thepipeyoumade).

Then, you write to the new process's standard input and read from its standard output. (This can be a little confusing, but the constants are defined from the child process's point of view. So since the child process has to read from its stadard input and write to its standard output, someone else has to write data into the child process's standard input and presumably is also reading the data written into the child process's standard output.)

So,

childsSTDIN = thepipeyoumade[STDIN] 
integer b = pipeio:write(childsSTDIN, "some data") 
 
childsSTDOUT = thepipeyoumade[STDOUT] 
integer n = pipeio:read(childsSTDOUT, number_of_bytes_to_read) 

When you are done, clean up by doing pipeio:kill(thepipeyoumade) (maybe this should have been better named close_process() or cleanup() or something, but kill matches the API call name that is used internally).

From the process side (if it's an Euphoria process), simply read your data as normal from stdin (gets(0) or getc(0), etc) and write your data to stdout (puts(1, "data", etc) and you're done.

One annoying thing about pipeio is that if data isn't ready, it makes you wait instead of just saying "0 bytes read" or something. On *nix, here's how to fix that.

include std/pipeio.e 
 
object thepipeyoumade = pipeio:create() 
thepipeyoumade = pipeio:exec("command line here", thepipeyoumade) 
 
include std/dll.e 
 
object STDLIB = dll:open_dll({ "libc.so", "libc.dylib", "" }) 
object FNCTL = dll:define_c_func(STDLIB, "fnctl",   {dll:C_INT, dll:C_INT, dll:C_INT}, dll:C_INT) 
object O_NONBLOCK = 2048, O_ASYNC = 8192, F_SETFL = 4 
 
c_func(FNCTL, {thepipeyoumade[STDIN], F_SETFL, or_bits(O_NONBLOCK, O_ASYNC)}) 
c_func(FNCTL, {thepipeyoumade[STDOUT], F_SETFL, or_bits(O_NONBLOCK, O_ASYNC)}) 
c_func(FNCTL, {thepipeyoumade[STDERR], F_SETFL, or_bits(O_NONBLOCK, O_ASYNC)}) 
 
childsSTDIN = thepipeyoumade[STDIN] 
integer b = pipeio:write(childsSTDIN, "some data") 
 
childsSTDOUT = thepipeyoumade[STDOUT] 
integer n = pipeio:read(childsSTDOUT, number_of_bytes_to_read) 
 
pipeio:kill(thepipeyoumade) 

4. Re: Pipe Input/Output

• Posted by achury Jul 08, 2015
• 1577 views

Please help me. What is that I'm doing bad?

include std/pipeio.e 
include std/io.e 
 
object Correo 
object childsSTDIN 
sequence MailString 
 
Correo = pipeio:create() 
? Correo 
Correo=pipeio:exec("c:\\sendmail\\sendmail.exe -t -i ", Correo) 
? Correo 
childsSTDIN = Correo[pipeio:STDIN] 
 
MailString="To: achury@cantv.net\nFrom: marcoachury@gmail.com\nSubject: Just a test\n\nJust a test\n\n" & io:EOF 
 
integer b = pipeio:write(childsSTDIN,  MailString) 
? b 
pipeio:kill(Correo) 

6. Re: Pipe Input/Output

• Posted by jmduro Jul 08, 2015
• 1570 views

Here is a working example I use almost every day.

public function execCommand(sequence cmd) 
  sequence s = "" 
  object z = pipe:create() 
  object p = pipe:exec(cmd, z) 
  if atom(p) then 
    logMsg(sprintf("Failed to exec() with error %x", pipe:error_no())) 
    pipe:kill(p) 
	return -1 
  end if 
  object c = pipe:read(p[pipe:STDOUT], 256) 
  while sequence(c) and length(c) do 
    s &= c 
    if atom(c) then 
	  logMsg(sprintf("Failed on read with error %x", pipe:error_no())) 
      pipe:kill(p) 
	  return -1 
    end if 
    c = pipe:read(p[pipe:STDOUT], 256) 
  end while 
  --Close pipes and make sure process is terminated 
  pipe:kill(p) 
  return s 
end function 

8. Re: Pipe Input/Output

• Posted by achury Jul 08, 2015
• 1551 views

Thanks a lot for your help. Now I have nice mailer that dont requires to create temp files.

Replace kill with close solved my problem. This is the final code if someone needed.

include std/pipeio.e 
 
object Correo 
object childsSTDIN 
sequence MailString 
 
Correo = pipeio:create() 
 
Correo=pipeio:exec("c:\\sendmail\\sendmail.exe -t -i ", Correo) 
-- Sendmail from http://glob.com.au/sendmail/ 
 
childsSTDIN = Correo[pipeio:STDIN] 
 
-- To: and From: may be defined on sendmail.ini or included on MailString 
-- Double \n may be required after email headers 
 
MailString="Subject: Just a subject\n\nJust a body text\n\n" 
 
integer b = pipeio:write(childsSTDIN,  MailString) 
 
Correo=pipeio:close(0)