[ET Trac] [Einstein Toolkit] #1548: stdout redirection in multithreading scenario

[Einstein Toolkit]

#1548: stdout redirection in multithreading scenario
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  Reporter:  gzheng@…             |       Owner:                     
      Type:  defect               |      Status:  reopened           
  Priority:  major                |   Milestone:                     
 Component:  Cactus               |     Version:  development version
Resolution:                       |    Keywords:  stdout redirection 
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Comment (by rhaas):

 After Gengbing's talk today and studying #1618, would it be possible to do
 something as simple as this:
 {{{
 static AMPI_TLS FILE *CCTK_stdout = NULL;
 ...
 CCTKi_CommandLineFinished(...)
 {
 ...
 if(CCTK_MyProc(cctkGH) != 0) {
   CCTK_stdout = fopen("CCTK_ProcX.out");
 } else {
   // or just = stdout since we never close the file handle anyway
   CCTK_stdout = freopen(stdout);
 }
 ...
 }
 }}}
 ?

 We would then use CCTK_stdout in CCTK_VWarn etc. We'd still keep the
 {{{dup()}}} code around for the benefit of Fortran code that does
 {{{write(*,*)}}} etc. and requires redirecting the OS level file
 descriptors (which may need some code to protect against multiple AMPI
 ranks trying to redirect the same file descriptor). Such Fortran code
 would not be compatible with AMPI (not much we can do about this I think
 unless we want to change the file descriptors each time the thread
 changes).

 This would make this ticket a sub-ticket of #1618 (supporting AMPI).

-- 
Ticket URL: <https://trac.einsteintoolkit.org/ticket/1548#comment:4>
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