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56 lines
2.4 KiB
TeX
56 lines
2.4 KiB
TeX
\section{Standard Module \sectcode{traceback}}
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\label{module-traceback}
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\stmodindex{traceback}
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This module provides a standard interface to format and print stack
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traces of Python programs. It exactly mimics the behavior of the
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Python interpreter when it prints a stack trace. This is useful when
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you want to print stack traces under program control, e.g. in a
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``wrapper'' around the interpreter.
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The module uses traceback objects --- this is the object type
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that is stored in the variables \code{sys.exc_traceback} and
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\code{sys.last_traceback}.
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\obindex{traceback}
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The module defines the following functions:
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\begin{funcdesc}{print_tb}{traceback\optional{, limit}}
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Print up to \var{limit} stack trace entries from \var{traceback}. If
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\var{limit} is omitted or \code{None}, all entries are printed.
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\end{funcdesc}
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\begin{funcdesc}{extract_tb}{traceback\optional{, limit}}
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Return a list of up to \var{limit} ``pre-processed'' stack trace
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entries extracted from \var{traceback}. It is useful for alternate
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formatting of stack traces. If \var{limit} is omitted or \code{None},
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all entries are extracted. A ``pre-processed'' stack trace entry is a
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quadruple (\var{filename}, \var{line number}, \var{function name},
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\var{line text}) representing the information that is usually printed
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for a stack trace. The \var{line text} is a string with leading and
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trailing whitespace stripped; if the source is not available it is
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\code{None}.
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\end{funcdesc}
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\begin{funcdesc}{print_exception}{type, value, traceback\optional{, limit}}
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Print exception information and up to \var{limit} stack trace entries
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from \var{traceback}. This differs from \function{print_tb()} in the
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following ways: (1) if \var{traceback} is not \code{None}, it prints a
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header \samp{Traceback (innermost last):}; (2) it prints the
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exception \var{type} and \var{value} after the stack trace; (3) if
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\var{type} is \exception{SyntaxError} and \var{value} has the appropriate
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format, it prints the line where the syntax error occurred with a
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caret indicating the approximate position of the error.
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\end{funcdesc}
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\begin{funcdesc}{print_exc}{\optional{limit}}
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This is a shorthand for `\code{print_exception(sys.exc_type,}
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\code{sys.exc_value,} \code{sys.exc_traceback,} \var{limit}\code{)}'.
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\end{funcdesc}
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\begin{funcdesc}{print_last}{\optional{limit}}
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This is a shorthand for `\code{print_exception(sys.last_type,}
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\code{sys.last_value,} \code{sys.last_traceback,} \var{limit}\code{)}'.
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\end{funcdesc}
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