Tcl_Access

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  permis-
                                   sions, respectively.   F_OK  just  requests
                                   checking for the existence of the file.

       stat   *statPtr   (out)     The structure that contains the result.
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DESCRIPTION
       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 functions 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 functions.  This
       allows the possibity 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 system  object)  whose
       name  is  pathname.   If pathname is a symbolic link on Unix, then per-
       missions 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 regard-
       ing device, inode (always 0 on Windows), priviledge 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                                   8.1                        Tcl_Access(3)