[Bug 1195394] [NEW] redirect program output into a log file does not seem to work properly when there is sleep in the program

[Yuan Song]

Public bug reported:

Redirect does not seem to work properly when program uses a sleep.   I
used the following test program.  It works well if I do not redirect the
output   If I redirect the output to a file, I won't see anything in the
file.  tail -f does not show me anything.  I can do redirect if I remove
the sleep.  I am using  64bits 13.04 with 3.8.0-25-generic #37 kernel.
bash version is version 4.2.45(1).

#include <stdio.h>
#include <sys/time.h>
#include <time.h>

int main()
{
 struct timeval tv;
 struct tm* ltm;

 while(1)
{
 sleep(1);
 gettimeofday(&tv, NULL);
 ltm = localtime(&tv.tv_sec);

   printf("%s\n", asctime(ltm));
}
}

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: bash 4.2-5ubuntu3
ProcVersionSignature: Ubuntu 3.8.0-25.37-generic 3.8.13
Uname: Linux 3.8.0-25-generic x86_64
ApportVersion: 2.9.2-0ubuntu8.1
Architecture: amd64
Date: Thu Jun 27 11:59:39 2013
InstallationDate: Installed on 2013-04-02 (86 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: bash
UpgradeStatus: Upgraded to raring on 2013-06-23 (3 days ago)

** Affects: bash (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug raring

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https://bugs.launchpad.net/bugs/1195394

Title:
  redirect program output into a log file does not seem to work properly
  when there is sleep in the program

Status in “bash” package in Ubuntu:
  New

Bug description:
  Redirect does not seem to work properly when program uses a sleep.   I
  used the following test program.  It works well if I do not redirect
  the output   If I redirect the output to a file, I won't see anything
  in the file.  tail -f does not show me anything.  I can do redirect if
  I remove the sleep.  I am using  64bits 13.04 with 3.8.0-25-generic
  #37 kernel.  bash version is version 4.2.45(1).

  #include <stdio.h>
  #include <sys/time.h>
  #include <time.h>

  int main()
  {
   struct timeval tv;
   struct tm* ltm;

   while(1)
  {
   sleep(1);
   gettimeofday(&tv, NULL);
   ltm = localtime(&tv.tv_sec);

     printf("%s\n", asctime(ltm));
  }
  }

  ProblemType: Bug
  DistroRelease: Ubuntu 13.04
  Package: bash 4.2-5ubuntu3
  ProcVersionSignature: Ubuntu 3.8.0-25.37-generic 3.8.13
  Uname: Linux 3.8.0-25-generic x86_64
  ApportVersion: 2.9.2-0ubuntu8.1
  Architecture: amd64
  Date: Thu Jun 27 11:59:39 2013
  InstallationDate: Installed on 2013-04-02 (86 days ago)
  InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
  MarkForUpload: True
  ProcEnviron:
   TERM=xterm
   PATH=(custom, no user)
   XDG_RUNTIME_DIR=<set>
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  SourcePackage: bash
  UpgradeStatus: Upgraded to raring on 2013-06-23 (3 days ago)

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