Tcl Source Code

https://www.tcl.tk/man/tcl/TclLib/OpenFileChnl.htm#M7 states for Tcl_OpenCommandChannel():

  If an error occurs while opening the channel, [...] In addition, 
  Tcl_OpenCommandChannel leaves an error message in the interpreter's
  result if interp is not NULL. 

The code in generic/TclPipe.c however states that interp cannot be NULL:

  Tcl_Channel
  Tcl_OpenCommandChannel(
      Tcl_Interp *interp, /* Interpreter for error reporting. Can NOT be NULL. */

And indeed, calling Tcl_OpenCommandChannel(NULL, ...) dumps core in case of an error when opening the pipeline (e.g. command not found).

=> Documentation should be adjusted: "interp cannot be NULL".

Fixed now in all active branches.

Thanks!