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Creates a modifiable copy of a version


ProductCommand type
ClearCasecleartool subcommand
ClearCase LTcleartool subcommand



checkout | co [ –res·erved ] [–unr·eserved [ –nma· ster ] ]
[ –out dest-pname | –nda· ta ] [ –pti·me ]
[ –bra·nch branch-pname | –ver·sion ] [ –nwa·rn ]
[ –c·omment comment | –cfi·le comment-file-pname | –cq·uery | –cqe·ach
| –nc·omment ][ –q·uery | –nq·uery ] pname ...


For one or more elements, the checkout command checks out a branch (typically, the most recent version on a branch). In most cases, this creates a writable copy of that version in the current view (the checked-out version), but see the “Checking Out a DO Version ” section. An appropriate message is displayed. For example:

Checked out "msg.c" from version "/main/bugfix/25"

If you are checking out in a UCM view, the view must be set to a UCM activity (see setactivity). Checked-out elements are added to the change set of the UCM activity you set.

A checkout record is created; it can be listed with the lscheckout command:

cmd-context lsco msg.c 
05-Aug.20:50 akp checkout version "msg.c" from \main\bugfix\25 (reserved) 

If an existing view-private object has the same name as an element being checked out, checkout responds as follows:

  • In a dynamic view, it displays this error message:

    Not a vob object: pname

    To check out the element, rename or remove the view-private object with the standard operating system command and enter the checkout command again.

  • In a snapshot view, the behavior is different for view-private directories and view-private files:
    • A view-private directory that corresponds to a directory in the VOB namespace is checked out. That is, checkout creates a checkout record in the VOB for the directory element. Any changes to the checked-out directory in the view are added to the VOB at checkin.
    • A view-private file with the same name as an element being checked out is treated as a hijacked file. checkout asks whether you want to use the file as the checked-out version; if you do not, the view-private file is renamed.

You must check out a directory before you use a command that changes its contents (mkelem, mkdir, rmname, ln, or mv). Each of these commands appends an appropriate line to the directory's checkout comment. For example, using mkelem to create a new element within a directory adds a line like this one:

Added file element "wel.c".

Reserved and Unreserved Checkouts

A version can have at most one reserved checkout and any number of unreserved checkouts. Performing a reserved checkout (without using the –version option) guarantees you the right to create a successor to the version you checked out. If several users perform unreserved checkouts, any one of those users (and only one) can create a successor version.

The predecessor version of your checked-out file may not be the latest on the branch from which you checked out your version; this situation can occur if the –version option or unreserved checkouts are used. In this case, you must merge from the latest version on the branch to your checked-out version before you can check in your version.

You can change the reserved state of a checked-out version with the reserve and unreserve commands.

MultiSite: Checking Out a Branch Mastered at Another Site

If the VOB containing the element is replicated, the checkout command fails if you try to check out a branch mastered by a different replica:

cleartool checkout –nc file1.txt 
cleartool: Error: Unable to perform operation "checkout" in replica 
"lexington" of VOB "/vobs/dev".
cleartool: Error: Master replica of branch "/main" is "london".
cleartool: Error: Unable to check out "file1.txt".

If you need to do work on a branch mastered by another replica, you have two choices:

  • Request mastership of the branch and wait until the mastership is transferred to your current replica before you check out the branch.
  • Check out the branch and do your work while waiting for mastership to be transferred. You can request mastership before or after checking out the branch. To check out the branch, use checkout –unreserved –nmaster, which performs a nonmastered checkout. When the mastership of the branch is transferred to your current replica, you may have to perform a merge before checking in your work. Therefore, do not use this option if you cannot merge versions of the element (for example, if the versions are in binary format).

To request mastership, ask the administrator at the master replica to transfer mastership or use the reqmaster command. Consult your ClearCase administrator to make sure mastership requests with reqmaster are enabled and that the replicas are at the correct feature level.

Nonstandard Checkouts

By default, the checkout command checks out these versions:

  • The most recent version on a branch, if you are using a dynamic view
  • The version currently loaded in the view, if you are using a snapshot view

To modify a different version, you can either use the –version option or create a subbranch at that version. (See the mkbranch reference page). Furthermore, from a single view, you can have only one checkout per element at a time.

Note: When you work in a snapshot view, the only version of a directory element that can be checked out is the version currently loaded in the view. Therefore, the –version and –branch options do not work.

When you use the –version option, you can specify the version either by setting your config spec to use that version or by specifying a version-extended pathname as the pname argument. After you make your changes, you must merge from the latest version of the element before you can perform a checkin.

You can check out a version that your config spec does not currently specify, either by using the –branch option or by specifying a pname argument that is a branch pathname (for example, msg.c@@/main/rel4_bugfix). In such cases, a warning message appears:

cleartool: Warning: Version checked out is different from version 
previously selected by view.

Checking Out a DO Version

(Dynamic view) If the version being checked out is a derived object (DO version), checkout attempts to winkin the DO to your view. If it cannot perform the winkin, it copies the DO's data instead. A winkin cannot be performed if you use the –out option to specify a destination in another VOB, or in a non-VOB location, such as /tmp.

For more information about the behavior of checked-out DO versions, see Building Software.


If the config spec specifies a version using a rule with a –mkbranch branch-type clause (see also config_spec), checkout works as follows:

  1. Creates a branch of type branch-type.
  2. Checks out (version 0 on) the new branch.

Except for some extra messages, the behavior is no different from an ordinary checkout. The checked-out version has the expected contents, because version 0 on the new branch has the same contents as the version at the branch point.

Note: (MultiSite sites) If the VOB is replicated, the current replica must master all the branch types specified in your config spec. Otherwise, auto-make-branch fails.

Multiple-Level Auto-Make-Branch

A config spec can include a cascade of auto-make-branch rules, causing checkout to create multiple branching levels at once. checkout keeps performing auto-make-branch until version 0 on the newly created branch is not selected by a rule with a –mkbranch clause. For example:

element * CHECKEDOUT
element * .../br2/LATEST
element * .../br1/LATEST -mkbranch br2
element * MYLABEL -mkbranch br1
element * /main/LATEST

If you check out an element in a view that currently selects the version labeled MYLABEL:

  1. A branch of type br1 is created at the MYLABEL version, following the the fourth rule.
  2. The third rule then selects the newly created version .../br1/0, so a branch of type br2 is created at that version.
  3. Version .../br1/br2/0 is checked out. The checked-out version has the same contents as the MYLABEL version and is selected by the first rule. When you edit and check in a new version, .../br1/br2/1, the view selects it with the second rule.

Checked-Out Files

Any checked-out file can be read, edited, and deleted like any ordinary file.

Dynamic Views

You have write permission on a checked-out file only if you have write permission on the set view's view storage directory. If you have write permission on the view storage directory for the view you are using, you have write permission on a checked-out file in that view.

Snapshot Views

The initial permissions on the checked-out file are determined by this algorithm:

  1. Start with the permissions of the element itself. (See the mkelem and protect reference pages.)
  2. Add a write permission when the element itself has a read permission (user, group, and/or other).
  3. (UNIX) Subtract read, write, and/or execute permissions according to your current umask(1) value.

You can change the permissions of the checked-out file with the standard UNIX chmod(1) command or by changing the Windows file properties, but you must use the protect command to change the permissions of the element itself.

Checked-Out But Removed Files

There may be no object in the view located at the pathname of the checked-out version. This can happen if any of these conditions are true:

  • You have deleted the file.
  • You renamed the file.
  • You used checkout –out to copy the checked-out version to another location.
  • You used checkout –ndata to create only a checkout record for the version.
  • A permission problem occurred and checkout was unable to write the file. In this case, cancel the checkout (use uncheckout), fix the permission problem, and check out the file again.

An OS-level listing command does not show the missing file, but the cleartool ls command displays the pathname of the checked-out version with the notation checked out but removed.



You must have one of the following identities:

  • Element owner
  • Element group member
  • VOB owner
  • root (UNIX)
  • Member of the ClearCase administrators group (ClearCase on Windows)
  • Local administrator of the ClearCase LT server host (ClearCase LT on Windows)

Additional restrictions on UNIX:

  • If the element's setuid bit is set, only the element's owner, the VOB owner, or root can check out the version.
  • If the element's setgid bit is set, only a member of the element's group, the VOB owner, or root can check out the version.


An error occurs if one or more of these objects are locked: VOB, element type, branch type, element, branch.


(Replicated VOBs) Your current replica must master the branch you are checking out unless you use –unreserved –nmaster.


Reserved and Unreserved Checkouts

–res·erved unless a different default is specified in profile_ccase.

Reserves the branch: no user in another view can perform a reserved checkout of the same branch (but any number of unreserved checkouts can be performed); no new versions can be created on the branch until your checkout is changed to unreserved with unreserve or resolved with checkin or uncheckout. If you specify both –reserved and –unreserved, this command performs a reserved checkout if possible; otherwise, an unreserved checkout.

–unr·eserved [ –nma·ster ]
Leaves the branch unreserved; other users, in other views, can check out the same version (but at most one of the checkouts can be reserved).

With –nmaster, checks out the branch even if the current replica does not master the branch. Do not use this option if you cannot merge versions of the element.

For a discussion of how new versions are created from reserved and unreserved checkouts, see the checkin reference page.

Creation of Checked-Out Version in View

(File elements) Creates in the view:
  • A view-private file for the version being checked out with the same pathname as the element (dynamic view).

  • A modifiable copy of the version being checked out with the same pathname as the element (snapshot view).

Exception: (Dynamic views) If the version being checked out is a derived object, it is winked in to the view.

–out dest-pname
(Does not apply to directories or DO versions) Creates a writable file under an alternate filename (perhaps in a different directory). No view-private file named pname is created. The cleartool ls command lists the element as checkedout but removed.

(Does not apply to directories) Creates a checkout record for the version, but does not create an editable file that contains its data. The ls command lists the file as checked out but removed. This option is useful for checking out files that will be overwritten (for example, staged binaries or other files that are copied into place).

Preserving Modification Time

In a dynamic view, checkout resets the file's modification time to the checkout time. In a snapshot view, checkout preserves the file's modification time.

Preserves the modification time of the file being checked out. This option is silently ignored when you use it in a snapshot view.

Nonstandard Checkouts

If pname specifies a particular branch, check out that branch, that is, the latest version on the branch. Otherwise, do the following:
  • In a dynamic view, check out the latest version on the branch.

  • In a snapshot view, check out the version that is currently in the view.

checkout creates a copy of each checked-out version and names it pname.

–bra·nch branch-pname
Specifies the branch whose most recent version is to be checked out. For example, to check out the latest version on branch ports, specify –branch \main\ports.

Allows the checkout of a version that is not the latest on its branch.

Suppressing Warning Messages

Warning messages are displayed.

Suppresses warning messages.

Event Records and Comments

Creates one or more event records, with commenting controlled by your .clearcase_profile file (default: –cqe). See the comments reference page. Comments can be edited with chevent.

–c·omment comment | –cfi·le comment-file-pname |–cq·uery | –cqe·ach | –nc·omment
Overrides the default with the option you specify. See the comments reference page.

Querying for the Resolution of Checkout Problems

No querying.

Query for the resolution of a checkout problem.

Do not query for the resolution of a checkout problem.

Element Argument


pname ...
Pathnames of one or more elements to be checked out.


The UNIX examples in this section are written for use in csh. If you use another shell, you may need to use different quoting and escaping conventions.

The Windows examples that include wildcards or quoting are written for use in cleartool interactive mode. If you use cleartool single-command mode, you may need to change the wildcards and quoting to make your command interpreter process the command appropriately.

In cleartool single-command mode, cmd-context represents the UNIX shell or Windows command interpreter prompt, followed by the cleartool command. In cleartool interactive mode, cmd-context represents the interactive cleartool prompt.

  • Check out the currently selected version of element hello.c, with no comment.

    cmd-context checkout –nc hello.c 
    Checked out "hello.c" from version "/main/3".

  • Check out the latest version on the rel2_bugfix branch of file msg.c, to another file name.

    cmd-context checkout –nc –branch \main\rel2_bugfix –out msg_test.c msg.c 
    Checked out "msg.c" from version "\main\rel2_bugfix\1".
    cmd-context ls msg_test.c msg.c
    msg.c@@\main\rel2_bugfix\CHECKEDOUT from \main\rel2_bugfix\1 [checked out but removed]

  • Check out the latest version on the rel2_bugfix branch of file msg.c, using an extended pathname to indicate the branch. This command checks out the same version as the preceding example.

    cmd-context checkout –nc msg.c@@/main/rel2_bugfix
    Checked out "msg.c" from version "/main/rel2_bugfix/1".

  • Check out an old version of the file hello.h, using an extended pathname to indicate the version. (Before you check in your revised version, you must perform a merge.)

    cmd-context checkout –c "attempt fix of old bug" -version hello.h@@\main\1 
    Checked out "hello.h" from version "\main\1". 

  • Perform an unreserved checkout of element hello.h. Provide a comment on the command line.

    cmd-context checkout –c "modify local defines"–unreserved hello.h 
    Checked out "hello.h" from version "/main/2"

  • Check out hello.c. Then, change your mind and cancel the checkout, removing the view-private copy.

    cmd-context checkout –nc hello.c 
    Checked out "hello.c" from version "\main\1". 
    cmd-context uncheckout –rm hello.c 
    Checkout cancelled for "hello.c". 



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