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50 lines
2.0 KiB
TeX
50 lines
2.0 KiB
TeX
\section{Standard Module \module{tempfile}}
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\label{module-tempfile}
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\stmodindex{tempfile}
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\indexii{temporary}{file name}
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\indexii{temporary}{file}
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This module generates temporary file names. It is not \UNIX{} specific,
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but it may require some help on non-\UNIX{} systems.
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Note: the modules does not create temporary files, nor does it
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automatically remove them when the current process exits or dies.
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The module defines a single user-callable function:
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\begin{funcdesc}{mktemp}{}
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Return a unique temporary filename. This is an absolute pathname of a
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file that does not exist at the time the call is made. No two calls
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will return the same filename.
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\end{funcdesc}
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The module uses two global variables that tell it how to construct a
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temporary name. The caller may assign values to them; by default they
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are initialized at the first call to \function{mktemp()}.
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\begin{datadesc}{tempdir}
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When set to a value other than \code{None}, this variable defines the
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directory in which filenames returned by \function{mktemp()} reside.
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The default is taken from the environment variable \envvar{TMPDIR}; if
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this is not set, either \file{/usr/tmp} is used (on \UNIX{}), or the
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current working directory (all other systems). No check is made to
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see whether its value is valid.
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\end{datadesc}
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\begin{datadesc}{template}
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When set to a value other than \code{None}, this variable defines the
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prefix of the final component of the filenames returned by
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\function{mktemp()}. A string of decimal digits is added to generate
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unique filenames. The default is either \file{@\var{pid}.} where
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\var{pid} is the current process ID (on \UNIX{}), or \file{tmp} (all
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other systems).
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\end{datadesc}
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\strong{Warning:} if a \UNIX{} process uses \code{mktemp()}, then
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calls \function{fork()} and both parent and child continue to use
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\function{mktemp()}, the processes will generate conflicting temporary
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names. To resolve this, the child process should assign \code{None}
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to \code{template}, to force recomputing the default on the next call
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to \function{mktemp()}.
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