gawk: Execution Stack

1 
1 14.3.4 Working with the Stack
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1 
1 Whenever you run a program that contains any function calls, 'gawk'
1 maintains a stack of all of the function calls leading up to where the
1 program is right now.  You can see how you got to where you are, and
1 also move around in the stack to see what the state of things was in the
1 functions that called the one you are in.  The commands for doing this
1 are:
1 
1 'backtrace' [COUNT]
1 'bt' [COUNT]
1 'where' [COUNT]
1      Print a backtrace of all function calls (stack frames), or
1      innermost COUNT frames if COUNT > 0.  Print the outermost COUNT
1      frames if COUNT < 0.  The backtrace displays the name and arguments
1      to each function, the source file name, and the line number.  The
1      alias 'where' for 'backtrace' is provided for longtime GDB users
1      who may be used to that command.
1 
1 'down' [COUNT]
1      Move COUNT (default 1) frames down the stack toward the innermost
1      frame.  Then select and print the frame.
1 
1 'frame' [N]
1 'f' [N]
1      Select and print stack frame N.  Frame 0 is the currently
1      executing, or "innermost", frame (function call); frame 1 is the
1      frame that called the innermost one.  The highest-numbered frame is
1      the one for the main program.  The printed information consists of
1      the frame number, function and argument names, source file, and the
1      source line.
1 
1 'up' [COUNT]
1      Move COUNT (default 1) frames up the stack toward the outermost
1      frame.  Then select and print the frame.
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