/** @file  ../include/sys/stat.h

 @internalComponent

 */

 /** @fn  chmod(const char *_path, mode_t _mode)

 @param _path

 @param _mode

 Note: This description also covers the following functions -

  fchmod()  lchmod() 

 @return   Upon successful completion, the value 0 is returned; otherwise the

 value -1 is returned and the global variable errno is set to indicate the

 error.

 @code

   #include < sys/stat.h > :

 @endcode

   The file permission bits of the file named specified by _path or referenced by the file descriptor fd are changed to _mode. The chmod system call verifies that the process owner (user) either owns

 the file specified by _path (or fd ),

 or

 is the super-user.

 The chmod system call follows symbolic links to operate on the target of the link

 rather than the link itself.

  The lchmod system call is similar to chmod but does not follow symbolic links.

  A mode is created from ored permission bit masks

 defined in  \#include \<sys/stat.h\> :

 @code

 #define S_IRWXU 0000700    // RWX mask for owner

 #define S_IRUSR 0000400    // R for owner 

 #define S_IWUSR 0000200    // W for owner 

 #define S_IXUSR 0000100    // X for owner 

 #define S_IRWXG 0000070    // RWX mask for group

 #define S_IRGRP 0000040    // R for group

 #define S_IWGRP 0000020    // W for group

 #define S_IXGRP 0000010    // X for group

 #define S_IRWXO 0000007    // RWX mask for other

 #define S_IROTH 0000004    // R for other

 #define S_IWOTH 0000002    // W for other

 #define S_IXOTH 0000001    // X for other

 #define S_ISUID 0004000    // set user id on execution

 #define S_ISGID 0002000    // set group id on execution

 #ifndef __BSD_VISIBLE

 #define S_ISTXT 0001000    // sticky bit

 #endif

 @endcode

  Notes :

  Sticky bit and set id on execution are not supported.

  Permission values for group and others are ignored as there is no concept of 

   group and others on the Symbian OS.

  The flag bits S_IXUSR, S_IXGRP & S_IXOTH are ignored as execute permissions on a file are meaningless on Symbian OS.

   An attempt to change file permission to write-only changes the file permission 

   to read-write.

 Either or both of S_IRUSR or S_IWUSR bits must be set in the _mode argument, else chmod fails with EINVAL. 

  Permissions for directories are ignored.

  000 mode is treated as invalid mode as Symbian OS cannot have entries with 

   both read and write permissions absent.

 Examples:

 @code

 /*Detailed description: This test code demonstartes usage of chmod system call, it

  * changes mode of file Example.txt in the current working directory to read-only.

  * Preconditions: Example.txt file should be present in the current working directory.

  */

 int main()

 {

   if(chmod("Example.txt" , 0444) < 0 )  

   {

      printf("change mode of file Example.txt failed");

      return -1;

   }

   printf("Chmod system call successful");

   return 0;

 }

 @endcode

  Output

 @code

 Chmod system call successful

 @endcode

 @code

 /* Detailed description : This sample code demonstrates the usage of fchmod system call, this code

  * changes mode of file Example.txt using fchmod system call.

  */

 #include <sys/types.h>

 #include <sys/stat.h>

 #include <fcntl.h>

 int main()

 {

  int fd = 0;

  fd = open("Example.txt" , O_CREAT | O_RDWR , 0666);

  if(fd < 0 )   {

     printf("Failed to open file Example.txt");

     return -1;

  }

  if(fchmod(fd , 0444) < 0 )  {

     printf("fchmod failed to change mode of file Example.txt");

     return -1;

  }

  printf("Fchmod call changed mode of Example.txt");

  return 0;

 }

 @endcode

  Output

 @code

 Fchmod call changed mode of Example.txt

 @endcode

 Limitations:

 KErrNotReady of Symbian error code is mapped to ENOENT, which typically means drive

 not found or filesystem not mounted on the drive.

 @see chmod()

 @see chown()

 @see open()

 @see stat()

 @capability Deferred @ref RFs::SetAtt(const TDesC16&, unsigned, unsigned)

 @publishedAll

 @externallyDefinedApi

 */

 /** @fn  fchmod(int fd, mode_t _mode)

 @param fd

 @param _mode

 Refer to  chmod() for the documentation

 @see chmod()

 @see chown()

 @see open()

 @see stat()

 @publishedAll

 @externallyDefinedApi

 */

 /** @fn  fstat(int fd, struct stat *st)

 @param fd

 @param st

 Refer to  stat() for the documentation

 Notes:

 If 'fd' refers to a shared memory object, the implementation updates only the st_uid, st_gid, st_size, 

 and st_mode fields in the stat structure pointed to by the 'st' argument .

 @see access()

 @see chmod()

 @see chown()

 @see utimes()

 @see symlink()

 @publishedAll

 @externallyDefinedApi

 */

 /** @fn  fstat64(int fd, struct stat64 *st)

 @param fd

 @param st

 For full documentation see: http://www.unix.org/version2/whatsnew/lfs20mar.html#3.0

 @see fstat()

 @publishedAll

 @externallyDefinedApi

 */

 /** @fn  lstat(const char *file_name, struct stat *buf)

 @param file_name

 @param buf

 Refer to  stat() for the documentation

 @see access()

 @see chmod()

 @see chown()

 @see utimes()

 @see symlink()

 @capability Deferred @ref RFs::Entry(const TDesC16&, TEntry&)

 @publishedAll

 @externallyDefinedApi

 */

 /** @fn  lstat64(const char *file_name, struct stat64 *buf)

 @param file_name

 @param buf

 For full documentation see: http://www.unix.org/version2/whatsnew/lfs20mar.html#3.0

 @see lstat()

 @publishedAll

 @externallyDefinedApi

 */

 /** @fn  __xstat(int, const char *file, struct stat *buf)

 @param file

 @param buf

 Refer to  stat() for the documentation

 @see access()

 @see chmod()

 @see chown()

 @see utimes()

 @see symlink()

 @publishedAll

 @released

 */

 /** @fn  __xstat64(int, const char *file, struct stat64 *buf)

 @param file

 @param buf

 For full documentation see: http://www.unix.org/version2/whatsnew/lfs20mar.html#3.0

 @see __xstat()

 @publishedAll

 @released

 */

 /** @fn  __lxstat(int, const char *file, struct stat *buf)

 @param file

 @param buf

 Refer to  stat() for the documentation

 @see access()

 @see chmod()

 @see chown()

 @see utimes()

 @see symlink()

 @publishedAll

 @released

 */

 /** @fn  __lxstat64(int, const char *file, struct stat64 *buf)

 @param file

 @param buf

 For full documentation see: http://www.unix.org/version2/whatsnew/lfs20mar.html#3.0

 @see __lxstat()

 @publishedAll

 @released

 */

 /** @fn  mkdir(const char *_path, mode_t _mode)

 @param _path

 @param _mode

 @return   The mkdir() function returns the value 0 if successful; otherwise the

 value -1 is returned and the global variable errno is set to indicate the

 error.

   The directory _path is created with the access permissions specified by _mode.

  Notes:

  _mode values and access permissions are ignored in Symbian OS.

  The default working directory of a process is initialized to C: \\private\\U ID 

   (UID of the calling application) and any data written into this directory persists between phone resets.

  The parent directory's time stamp is not updated when a new child is created.

  The newly created directory will be empty (i.e. it doesn't have "." and 

   ".." entries)

 Examples:

 @code

 /* Detailed description : This test code demonstrates usage of mkdir systemcall,

  * it creates function a  directory Example in current working directory.

  */

 int main()

 {

   if(mkdir("Example" , 0666) < 0 )  

   {

       printf("Directory creation failed");

       return -1;

   }

   printf("Directory Example created");

   return 0;

 }

 @endcode

  Output

 @code

 Directory Example created

 @endcode

 Limitations:

 The path parameter in mkdir() should not exceed 256 characters in length. 

 KErrNotReady of Symbian error code is mapped to ENOENT, which typically means drive

 not found or filesystem not mounted on the drive.

 The path given to mkdir() should be complete. Attempting to create a directory my calling mkdir("logs",0400|0200|0100) 

 will pass on emulator but fails on h/w because the cwd is taken as c:\private\uid3 on emulator and

 z:\private\uid3 on h/w. Since Z drive is a rom on h/w, mkdir() fails by setting errno to 13 on hardware.

 @see chmod()

 @see stat()

 @see umask()

 @capability Deferred @ref RFs::MkDir(const TDesC16&)

 @publishedAll

 @externallyDefinedApi

 */

 /** @fn  mkfifo(const char *pathname, mode_t mode)

 @param pathname

 @param mode

 @return   The mkfifo function returns the value 0 if successful; otherwise the

 value -1 is returned and errno is set to indicate the error.

   The mkfifo system call

 creates a new FIFO(First In First Out) file with name path. The access permissions are

 specified by mode and restricted by the umask of the calling process.

 With the current implementation, the use of umask has no effect.

  The FIFO's owner ID and group ID are set to root.

  Please note that running stat on a FIFO file does not provide modification 

   time information (it provides the creation time). Use fstat on the fd to retrieve the last modified 

   time.

 Examples:

 @code

 #include <sys/types.h>

 #include <sys/stat.h>

 #include <stdio.h>

 int main(void)

 {

     char *pathname = "C:\XXX";

     mode_t mode = 0666;

     if (mkfifo(pathname, mode) == -1) {

         printf("mkfifo() failed");

     }

     return 0;

 }

 @endcode

 @see chmod()

 @see stat()

 @see umask()

 Limitations:

 KErrNotReady of Symbian error code is mapped to ENOENT, which typically means drive

 not found or filesystem not mounted on the drive.

 @capability Deferred @ref RFs::Delete(const TDesC16&)

 @publishedAll

 @externallyDefinedApi

 */

 /** @fn  stat(const char *name, struct stat *st)

 @param name

 @param st

 Note: This description also covers the following functions -

  lstat()  fstat()  __xstat()  __lxstat() 

 @return   Upon successful completion, the value 0 is returned; otherwise the

 value -1 is returned and the global variable errno is set to indicate the error.

 @code

  st_dev The numeric ID of the device containing the file.

  st_ino The file's inode number.

  st_nlink

   The number of hard links to the file.

 @endcode

 @code

  st_atime Time when file data last accessed.

  Changed by the .Xr utimes 2, read and readv system calls.

  st_mtime Time when file data last modified.

  Changed by the mkdir, mkfifo, mknod, utimes, write and writev system calls.

  st_ctime Time when file status was last changed (inode data modification).

  Changed by the chmod, chown, creat, link, mkdir, mkfifo, mknod, rename, rmdir, symlink, truncate, unlink, utimes, write and writev system calls.

  st_birthtime

   Time when the inode was created.

 @endcode

 @code

  st_size The file size in bytes.

  st_blksize

   The optimal I/O block size for the file.

  st_blocks The actual number of blocks allocated for the file in 512-byte units.

  As short symbolic links are stored in the inode, this number may

  be zero.

 @endcode

 @code

  st_uid The user ID of the file's owner.

  st_gid The group ID of the file.

  st_mode

   Status of the file (see below).

 @endcode

 @code

  Test for a block special file.

  Test for a character special file.

  Test for a directory.

  Test for a pipe or FIFO special file.

  Test for a symbolic link. NOTE: Inode structure is not supported by Symbian OS and hence link count updation is not possible.

  Check for symbolic link would always fail because of this reason.

  Test for a regular file.

  Test for a socket.

  Test for a whiteout.

 @endcode

   The stat system call obtains information about the file pointed to by path. Read, write or execute

 permission of the named file is not required, but all directories

 listed in the path name leading to the file must be searchable.

  The lstat system call is like stat except in the case where the named file is a symbolic link,

 in which case lstat returns information about the link,

 while stat returns information about the file the link references.

  The fstat system call obtains the same information about an open file

 known by the file descriptor fd.

  The __xstat and __lxstat system calls are exactly similar to stat and lstat functionality.

  The sb argument is a pointer to a stat structure as defined by \#include \<sys/stat.h\> and into which information is 

   placed concerning the file.

  The fields of struct stat

 related to the file system are as follows: 

 @code

 st_dev The numeric ID of the device containing the file. 

 st_ino The file's inode number. 

 st_nlink  The number of hard links to the file.

 @endcode

  The st_dev and st_ino fields together identify the file uniquely within the system.

  The time-related fields of struct stat

 are as follows: 

 st_atime Time when file data last accessed.

 Changed by the .Xr utimes 2, read and readv system calls. 

 st_mtime Time when file data last modified.

 Changed by the mkdir, mkfifo, mknod, utimes, write and writev system calls. 

 st_ctime Time when file status was last changed (inode data modification).

 Changed by the chmod, chown, creat, link, mkdir, mkfifo, mknod, rename, rmdir, symlink, truncate, unlink, utimes, write and writev system calls. st_birthtime  Time when the inode was created.

  If _POSIX_SOURCE is not defined, the time-related fields are defined as: 

 @code

 #ifndef _POSIX_SOURCE

 #define st_atime st_atimespec.tv_sec

 #define st_mtime st_mtimespec.tv_sec

 #define st_ctime st_ctimespec.tv_sec

 #endif

 @endcode

  The size-related fields of the struct stat

 are as follows: 

 st_size The file size in bytes. 

 st_blksize  The optimal I/O block size for the file. st_blocks The actual number of blocks allocated for the file in 512-byte units.

 As short symbolic links are stored in the inode, this number may

 be zero.

  The access-related fields of struct stat

 are as follows: 

 st_uid The user ID of the file's owner. 

 st_gid The group ID of the file. 

 st_mode  Status of the file (see below).

  The status information word st_mode has the following bits: 

 @code

 #define S_IFMT   0170000  // type of file

 #define S_IFIFO  0010000  // named pipe (fifo) 

 #define S_IFCHR  0020000  // character special 

 #define S_IFDIR  0040000  // directory 

 #define S_IFBLK  0060000  // block special 

 #define S_IFREG  0100000  // regular 

 #define S_IFLNK  0120000  // symbolic link 

 #define S_IFSOCK 0140000  // socket 

 #define S_IFWHT  0160000  // whiteout 

 #define S_ISUID  0004000  // set user id on execution 

 #define S_ISGID  0002000  // set group id on execution 

 #define S_ISVTX  0001000  // save swapped text even after use 

 #define S_IRUSR  0000400  // read permission, owner 

 #define S_IWUSR  0000200  // write permission, owner 

 #define S_IXUSR  0000100  // execute/search permission, owner 

 @endcode

  For a list of access modes, see \#include \<sys/stat.h\> access and chmod The following macros are available to 

   test whether a st_mode value passed in the m argument corresponds to a file of the specified type: S_ISBLK (m); Test for a block special file. S_ISCHR (m); Test for a character special file. S_ISDIR (m); Test for a directory. S_ISFIFO (m); Test for a pipe or FIFO special file. S_ISLNK (m); Test for a symbolic link. NOTE: Inode structure is not supported by Symbian OS and hence link count updation is not possible.

 Check for symbolic link would always fail because of this reason. S_ISREG (m); Test for a regular file. S_ISSOCK (m); Test for a socket. S_ISWHT (m); Test for a whiteout.

  The macros evaluate to a non-zero value if the test is true

 or to the value 0 if the test is false.

  Note: To obtain correct timestamps of FIFOs use fstat instead of stat call.

 Examples:

 @code

 /* Detailed description: Sample usage of stat system call

  * Preconditions: Example.txt file should be present in working directory 

  */

 #include <fcntl.h>

 #include <unistd.h>

 #include <sys/types.h>

 #include <sys/stat.h>

 int main()

 {

   struct stat buf;

    if(stat("Example.txt"  , &buf;) < 0 )

    {

       printf("Failed to stat Example.txt");

       return -1;

    }

    printf("Stat system call succeeded");

    return 0;

  }

 /*

  * Detailed description: Sample usage of fstat system call

  *

  */

 #include <fcntl.h>

 #include <unistd.h>

 #include <sys/types.h>

 #include <sys/stat.h>

 int main()

 {

   struct stat buf;

    int fd = open("Example.txt" , O_RDONLY | O_CREAT  , 0666);

    if(fstat(fd  , &buf;) < 0 ) 

    {

       printf("Failed to stat Example.txt");

       return -1;

    }

    printf("Stat system call succeeded");

    close(fd);

    return 0;

  }

 @endcode

  Output

 @code

 Stat system call succeeded

 @endcode

  Output

 @code

 Stat system call succeeded

 @endcode

 Limitations:

 The path parameters of the stat() and lstat() functions should not exceed 256 characters each in length. 

 KErrNotReady of Symbian error code is mapped to ENOENT, which typically means drive

 not found or filesystem not mounted on the drive.

 @see access()

 @see chmod()

 @see chown()

 @see utimes()

 @see symlink()

 @capability Deferred @ref RFs::Entry(const TDesC16&, TEntry&)

 @publishedAll

 @externallyDefinedApi

 */

 /** @fn  stat64(const char *name, struct stat64 *st)

 @param name

 @param st

 @return   Upon successful completion, the value 0 is returned; otherwise the

 value -1 is returned and the global variable errno is set to indicate the error.

 For full documentation see: http://www.unix.org/version2/whatsnew/lfs20mar.html#3.0

 @see stat()

 @publishedAll

 @externallyDefinedApi

 */

 /** @fn  umask(mode_t cmask)

 @param cmask

 @return   This function always returns MASK_RWUSR.

   This function is build supported but not available functionally. Symbian 

 OS does not support multiple users and groups

 @publishedAll

 @externallyDefinedApi

 */

 /** @struct stat 

 This structure provides detailed information about a file. The information returned depends on the type of file and/or the file system on which the file resides.

 Includes following members,

 @publishedAll

 @externallyDefinedApi

 */

 /** @var stat::st_dev

 inode's device

 */

 /** @var stat::st_ino

 inode's number

 */

 /** @var stat::st_mode

 inode protection mode

 */

 /** @var stat::st_nlink

 number of hard links

 */

 /** @var stat::st_uid

 user ID of the file's owner

 */

 /** @var stat::st_gid

 group ID of the file's group

 */

 /** @var stat::st_rdev

 device type

 */

 /** @var stat::st_atimespec

 time of last access

 */

 /** @var stat::st_mtimespec

 time of last data modification

 */

 /** @var stat::st_ctimespec

 time of last file status change

 */

 /** @var stat::st_size

 file size, in bytes

 */

 /** @var stat::st_blocks

 blocks allocated for file 

 */

 /** @var stat::st_blksize

 optimal blocksize for IO

 */

 /** @var stat::st_flags

 user defined flags for file

 */

 /** @var stat::st_gen

 file generation number

 */

 /** @struct stat64 

 The stat64 structure is similar to the stat structure, except that it is capable of returning information about files that are larger than 2 gigabytes.

 This structure provides detailed information about a file. The information returned depends on the type of file and/or the file system on which the file resides.

 Includes following members,

 @publishedAll

 @externallyDefinedApi

 */

 /** @var stat64::st_dev

 inode's device

 */

 /** @var stat64::st_ino

 inode's number

 */

 /** @var stat64::st_mode

 inode protection mode

 */

 /** @var stat64::st_nlink

 number of hard links

 */

 /** @var stat64::st_uid

 user ID of the file's owner

 */

 /** @var stat64::st_gid

 group ID of the file's group

 */

 /** @var stat64::st_rdev

 device type

 */

 /** @var stat64::st_atimespec

 time of last access

 */

 /** @var stat64::st_mtimespec

 time of last data modification

 */

 /** @var stat64::st_ctimespec

 time of last file status change

 */

 /** @var stat64::st_size

 file size, in bytes

 */

 /** @var stat64::st_blocks

 blocks allocated for file 

 */

 /** @var stat64::st_blksize

 optimal blocksize for IO

 */

 /** @var stat64::st_flags

 user defined flags for file

 */

 /** @var stat64::st_gen

 file generation number

 */

 /** @def S_IRWXU	

 RWX mask for owner

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IRUSR

 R for owner

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IWUSR

 W for owner

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IXUSR

 X for owner

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IFMT

 type of file mask

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IFIFO

 named pipe (fifo)

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IFCHR

 character special 

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IFDIR

 directory

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IFBLK

 block special

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IFREG	

 regular

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IFLNK

 symbolic link 

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_ISDIR(m)

 directory.

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_ISCHR(m)

 char special.

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_ISLNK(m)

 symbolic link

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_ISBLK(m)

 block special

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_ISREG(m)

 regular file 

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_ISFIFO(m)

 fifo or socket

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_ISUID

 set user id on execution

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_ISGID

 set group id on execution

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IRWXG

 RWX mask for group

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IRGRP

 R for group

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IWGRP

 W for group

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IXGRP

 X for group

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IRWXO

 RWX mask for other

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IROTH

 R for other

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IWOTH

 W for other

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_IXOTH

 X for other

 @publishedAll

 @externallyDefinedApi

 */

 /** @def S_ISVTX

 save swapped text even after use 

 @publishedAll

 @externallyDefinedApi

 */