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Creating temporary files

The C stdio package has two function calls related to the creation of temporary files: tmpFile and tmpnam. The Glib too has similar functions in its api such as g_mkstemp, g_file_open_tmp and so on. For someone programming in C, both of these approaches are excellent resources but someones scripting in Tcl more suitable approaches can be taken these C procedures will require a significant amount code to produce an effective binding which, may not offer worthwhile advantages.

The inclusion of a new command gnocl::tmpFile into to the core offers a convenient way of producing unique filenames. The command takes a single argument, an optional prefix, and returns a unique name with a randomized suffix.

If a prefix is specified:


puts [gnocl::tmpFile aaa]

/tmp/aaa.SYzqiJQA8Eeg4GZC1eDb

puts [gnocl::tmpFile bbb]

/tmp/bbb.VIT88L2zjeynnHn5dVfH

puts [gnocl::tmpFile ccc]

/tmp/ccc.3IkQqXjYtwDowshdjjCc


Without a prefix, the defaul 'TclScript' will be used.


puts [gnocl::tmpFile]

/tmp/TclScript.RcrXWEALx2ZDuS3DITli


If a greater level of control in need in the event of opening multiple temporary files then something along the line of the following procs may be of use.


proc tmp:open {} {

    set fname [gnocl::tmpFile]

    set fp [open $fname w]

    lappend ::tmp:files $fp $fname

    return $fp

}


proc tmp:files {} {

return [set ::tmp:files]

}


proc tmp:close {fp} {

close $fp

set ::tmp:files [dict remove [set ::tmp:files] $fp]

}


proc tmp:closeAll {} {

dict for {k v} [set ::tmp:files] {  close $k }

set ::tmp:files ""

}


proc tmp:unclosed {} {

return [dict keys [set ::tmp:files]]

}


set FP1 [tmp:open]

puts $FP1

set FP2 [tmp:open]


puts [tmp:files]

puts [tmp:unclosed]


tmp:close $FP2

puts [tmp:unclosed]


tmp:closeAll

puts [tmp:unclosed]

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