list_safe_reset_next(9) [centos man page]

LIST_SAFE_RESET_NEXT(9) 					    Data Types						   LIST_SAFE_RESET_NEXT(9)

NAME

       list_safe_reset_next - reset a stale list_for_each_entry_safe loop

SYNOPSIS

       list_safe_reset_next(pos, n, member);

ARGUMENTS

       pos
	   the loop cursor used in the list_for_each_entry_safe loop

       n
	   temporary storage used in list_for_each_entry_safe

       member
	   the name of the list_struct within the struct.

DESCRIPTION

       list_safe_reset_next is not safe to use in general if the list may be modified concurrently (eg. the lock is dropped in the loop body). An
       exception to this is if the cursor element (pos) is pinned in the list, and list_safe_reset_next is called after re-taking the lock and
       before completing the current iteration of the loop body.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						   LIST_SAFE_RESET_NEXT(9)

foreach(n)						       Tcl Built-In Commands							foreach(n)

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NAME

       foreach - Iterate over all elements in one or more lists

SYNOPSIS

       foreach varname list body
       foreach varlist1 list1 ?varlist2 list2 ...? body
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DESCRIPTION

       The  foreach command implements a loop where the loop variable(s) take on values from one or more lists.  In the simplest case there is one
       loop variable, varname, and one list, list, that is a list of values to assign to varname.  The body argument is a Tcl  script.	 For  each
       element	of  list  (in  order from first to last), foreach assigns the contents of the element to varname as if the lindex command had been
       used to extract the element, then calls the Tcl interpreter to execute body.

       In the general case there can be more than one value list (e.g., list1 and list2), and each value list can be associated  with  a  list	of
       loop  variables	(e.g.,	varlist1  and varlist2).  During each iteration of the loop the variables of each varlist are assigned consecutive
       values from the corresponding list.  Values in each list are used in order from first to last, and each value is used  exactly  once.   The
       total number of loop iterations is large enough to use up all the values from all the value lists.  If a value list does not contain enough
       elements for each of its loop variables in each iteration, empty values are used for the missing elements.

       The break and continue statements may be invoked inside body, with the same effect as in the for command.  Foreach returns an empty string.

EXAMPLES

       The following loop uses i and j as loop variables to iterate over pairs of elements of a single list.  set x {} foreach {i j} {a b c d e f}
       {
	   lappend x $j $i } # The value of x is "b a d c f e" # There are 3 iterations of the loop.

       The next loop uses i and j to iterate over two lists in parallel.  set x {} foreach i {a b c} j {d e f g} {
	   lappend x $i $j } # The value of x is "a d b e c f {} g" # There are 4 iterations of the loop.

       The two forms are combined in the following example.  set x {} foreach i {a b c} {j k} {d e f g} {
	   lappend x $i $j $k } # The value of x is "a d e b f g c {} {}" # There are 3 iterations of the loop.

SEE ALSO

       for(n), while(n), break(n), continue(n)

KEYWORDS

       foreach, iteration, list, looping

Tcl																	foreach(n)