From octave-maintainers-request at bevo dot che dot wisc dot edu  Tue Apr 13 07:52:11 1999
Subject:  popen2 strange behaviour within a function
From: Daniel Calvelo <dcalvelo at llorio dot lille dot inserm dot fr>
To: dcalvelo at llorio dot lille dot inserm dot fr, octave-maintainers@bevo.che.wisc.edu
Date: Wed, 14 Apr 1999 14:52:38 +0200

To: octave-maintainers at bevo dot che dot wisc dot edu
Cc: dcalvelo
Subject: popen2 strange behaviour within a function

Bug report for Octave 2.0.13.95 configured for i386-pc-linux-gnu

Description:
-----------

	When used insude a function, popen2 is unable to fecth output from 
child process if it is requested immediately after input feeding (at least on 
buffered input processes, like 'sort').

	In the interactive interpreter, it behaves as expected.

Repeat-By:
---------

Session transcript:
-------------------------------------------------------------------------------
Octave, version 2.0.13.95 (i386-pc-linux-gnu).
Copyright (C) 1996, 1997, 1998 John W. Eaton.
This is free software with ABSOLUTELY NO WARRANTY.
For details, type `warranty'.

octave:1> type ess
ess is the function defined from: /home/dcalvelo/lang/objc/ess.m

function e=ess(m)
   [in,out,pid] = popen2("sort","-n");
   fprintf(in,"%e\n",m)
   fclose(in)
   e=fscanf(out,"%e")
   fclose(out)
   waitpid(pid)
endfunction
octave:2> m=rand(10,1);
octave:3> ess(m)
ans = 19
ans = 0
e = [](0x1)
ans = 0
ans = 2920
ans = [](0x1)
octave:4>    [in,out,pid] = popen2("sort","-n");
octave:5>    fprintf(in,"%e\n",m)
ans = 19
octave:6>    fclose(in)
ans = 0
octave:7>    e=fscanf(out,"%e")
e =

  0.21444
  0.21812
  0.24042
  0.30588
  0.39884
  0.49816
  0.57548
  0.66786
  0.84487
  0.94233

octave:8>    fclose(out)
ans = 0
octave:9>    waitpid(pid)
ans = -1
octave:10> 
-------------------------------------------------------------------------------

Fix:
---

	Wish I knew <sigh>.

Configuration (please do not edit this section):
-----------------------------------------------

uname output:     Linux llorio 2.2.5 #2 Thu Apr 8 19:43:40 CEST 1999 i586 unknown
configure opts:   --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --with-g77 --enable-dl --enable-shared --enable-lite-kernel --host i386-linux
Fortran compiler: g77
FFLAGS:           -O2
F2C:              
F2CFLAGS:         
FLIBS:            -lg2c -lm -L/usr/lib/gcc-lib/i486-linux/egcs-2.91.60 -lm
CPPFLAGS:         
INCFLAGS:         -I/usr/include -I/usr/include/octave-2.0.13.95
C compiler:       egcc, version 2.7.2.3
CFLAGS:           -DHAVE_CONFIG_H -mieee-fp -O2
CPICFLAG:         -fPIC
C++ compiler:     c++, version 2.91.60 19981201 (egcs-1.1.1 release)
CXXFLAGS:         -DHAVE_CONFIG_H -mieee-fp -fno-rtti -fno-exceptions -fno-implicit-templates -O2
CXXPICFLAG:       -fPIC
LDFLAGS:          -s
LIBFLAGS:         -L/usr/lib/octave-2.0.13.95
RLD_FLAG:         -Xlinker -rpath -Xlinker /usr/lib/octave-2.0.13.95
TERMLIBS:         -lncurses
LIBS:             
LEXLIB:           
LIBPLPLOT:        
LIBDLFCN:         
DEFS:

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  -DHAVE_ATANH=1 -DHAVE_ERF=1 -DHAVE_ERFC=1 -DHAVE_ST_BLKSIZE=1
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