Tcl_Access(3)

Tcl_Access(3)        Tcl Library Procedures         Tcl_Access(3)

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NAME

     Tcl_Access, Tcl_Stat -  check  file  permissions  and  other
     attributes

SYNOPSIS

     #include <tcl.h>

     int
     Tcl_Access(path, mode)

     int
     Tcl_Stat(path, statPtr)

ARGUMENTS

     char *path (in)                    Native name of  the  file
                                        to  check  the attributes
                                        of.

     int mode (in)                      Mask consisting of one or
                                        more  of R_OK, W_OK, X_OK
                                        and F_OK.  R_OK, W_OK and
                                        X_OK   request   checking
                                        whether the  file  exists
                                        and  has  read, write and
                                        execute      permissions,
                                        respectively.   F_OK just
                                        requests checking for the
                                        existence of the file.

     struct stat *statPtr (out)         The structure  that  con-
                                        tains the result.
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DESCRIPTION

     As of  Tcl  8.4,  the  object-based  APIs  Tcl_FSAccess  and
     Tcl_FSStat  should  be  used in preference to Tcl_Access and
     Tcl_Stat, wherever possible.

     There are two reasons for calling  Tcl_Access  and  Tcl_Stat
     rather  than  calling system level functions access and stat
     directly.  First, the Windows implementation of  both  func-
     tions  fixes  some  bugs in the system level calls.  Second,
     both    Tcl_Access    and    Tcl_Stat    (as     well     as
     Tcl_OpenFileChannelProc)  hook  into  a linked list of func-
     tions.  This allows the possibility to reroute  file  access
     to alternative media or access methods.

     Tcl_Access checks whether the process would  be  allowed  to
     read, write or test for existence of the file (or other file

Tcl                     Last change: 8.1                        1

Tcl_Access(3)        Tcl Library Procedures         Tcl_Access(3)

     system object) whose name is pathname.   If  pathname  is  a
     symbolic link on Unix, then permissions of the file referred
     by this symbolic link are tested.

     On success (all  requested  permissions  granted),  zero  is
     returned.   On  error  (at least one bit in mode asked for a
     permission that is denied, or some other   error  occurred),
     -1 is returned.

     Tcl_Stat fills the stat structure statPtr  with  information
     about the specified file.  You do not need any access rights
     to the file to get this  information  but  you  need  search
     rights  to  all directories named in the path leading to the
     file.  The stat structure includes  info  regarding  device,
     inode (always 0 on Windows), privilege mode, nlink (always 1
     on Windows), user id (always 0 on Windows), group id (always
     0  on Windows), rdev (same as device on Windows), size, last
     access time, last modification time, and creation time.

     If path exists, Tcl_Stat returns 0 and the stat structure is
     filled  with  data.   Otherwise, -1 is returned, and no stat
     info is given.

KEYWORDS

     stat, access

Tcl                     Last change: 8.1                        2