BStatable

Member Functions

GetCreationTime(), SetCreationTime(), GetModificationTime(), SetModificationTime(), GetAccessTime(), SetAccessTime()

status_t BStatable::GetCreationTime(time_t *ctime) const

status_t BStatable::SetCreationTime(time_t ctime)

status_t BStatable::GetModificationTime(time_t *mtime) const

status_t BStatable::SetModificationTime(time_t mtime)

status_t BStatable::GetAccessTime(time_t *atime) const

status_t BStatable::SetAccessTime(time_t atime)

Warning

Access time is currently unused.

These function let you get and set the time at which the item was created, last modified, and last accessed (opened). The measure of time is given as seconds since (the beginning of ) January 1, 1970.

Note

The time quanta that stat uses is seconds; the rest of the BeOS measures time in microseconds (bigtime_t).

Return Code	Description
B_OK.	Success.
B_NOT_ALLOWED.	You tried to set a time field for a file on a read-only volume.
B_NO_MEMORY.	Couldn’t get the necessary resources to complete the transaction.
B_BAD_VALUE.	The node doesn’t exist (abstract entry).

GetNodeRef()

status_t BStatable::GetNodeRef(node_ref *nref) const

Copies the item’s node_ref structure into the nref argument, which must be allocated.

Typically, you use an node’s node_ref as a key to the Node Monitor by passing the node_ref structure to the watch_node() function. The Node Monitor watches the node for specific changes; see “The Node Monitor” section of this chapter for details.

As a convenience, you can use a node_ref structure to initialize a BDirectory object (through the constructor or BDirectory::SetTo() function).

Return Code	Description
B_OK.	Success.
B_NO_MEMORY.	Couldn’t get the necessary resources to complete the transaction.
B_BAD_VALUE.	The node doesn’t exist (abstract entry).

GetOwner(), SetOwner(), GetGroup(), SetGroup(), GetPermissions(), SetPermissions()

status_t BStatable::GetOwner(uid_t *owner) const

status_t BStatable::SetOwner(uid_t owner)

status_t BStatable::GetGroup(gid_t *group) const

status_t BStatable::SetGroup(gid_t group)

status_t BStatable::GetPermissions(mode_t *perms) const

status_t BStatable::SetPermissions(mode_t perms)

These functions set and get the owner, group, and read/write/execute permissions for the node:

• The owner identifier encodes the identity of the user that “owns” the file.

• The group identifier encodes the “group” that is permitted group access to the file (as declared by the permissions).

• The permissions value records nine “permission facts”: Whether the file can be read, written, and executed by the node’s owner, by users in the node’s group, and by everybody else (read/write/execute * owner/group/others = 9 items).

The uid_t, gid_t, and mode_t types used here are standard POSIX types. All three are 32-bit unsigned integers and are defined in posix/sys/types.h.

The owner and group encodings must match values found in the system’s user and group files (which are as currently unimplemented).

The permissions value is a combination of the following bitfield constants (defined in posix/sys/stat.h):

• S_IRUSR owner’s read bit.

• S_IWUSR owner’s write bit.

• S_IXUSR owner’s execute bit.

• S_IRGRP group’s read bit.

• S_IWGRP group’s write bit.

• S_IXGRP group’s execute bit.

• S_IROTH others’ read bit.

• S_IWOTH others’ write bit.

• S_IXOTH others’ execute bit.

For example:

/* Is a file readable by everybody? */
mode_t perms;
if (node.GetPermissions(&perms) < B_OK)
   /* handle the error... */

if (perms & S_ISROTH)
   // Yes it is
else
   // No it isn't

Return Code	Description
B_OK.	Success.
B_NOT_ALLOWED.	You tried to set permissions on a read-only volume.
B_BAD_VALUE.	The node doesn’t exist (abstract entry).

GetSize()

status_t BStatable::GetSize(off_t *size) const

Gets the size of the node’s data portion (in bytes). Only the “used” portions of the node’s file blocks are counted; the amount of storage the node actually requires (i.e. the number of blocks the node consumes) may be larger than the size given here.

The size measurement doesn’t include the node’s attributes.

Return Code	Description
B_OK.	Success.
B_NO_MEMORY.	Couldn’t get the necessary resources to complete the transaction.
B_BAD_VALUE.	The node doesn’t exist (abstract entry).

GetStat()

virtual status_t BStatable::GetStat(struct stat *st) const

GetStat() returns the stat structure for the node. The structure is copied into the st argument, which must be allocated. The BStatable object does not cache the stat structure; every time you call GetStat(), fresh stat information is retrieved.

Return Code	Description
B_OK.	Success.
B_NO_MEMORY.	Couldn’t get the necessary resources to complete the transaction.
B_BAD_VALUE.	The node doesn’t exist (abstract entry).

IsFile(), IsDirectory(), IsSymLink()

bool BStatable::IsFile() const

bool BStatable::IsDirectory() const

bool BStatable::IsSymLink() const

These functions return true if the node is a plain file, a directory, or a symbolic link, respectively.