1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
|
The tt(filesystem) functions tt(status) and tt(symlink_status)
retrieve or change statuses of file system entries. These
functions may be called with a final (optional) tt(error_code)
argument which is assigned an appropriate error code if they cannot perform
their tasks. If the argument is omitted the members throw exceptions if they
cannot perform their tasks:
itemization(
ithtq(status)(file_status status(path const &dest [, error_code &ec]))
(returns type and attributes of tt(dest). If tt(dest) is a symlink the
status of the link's destination is returned;)
ithtq(symlink_status)(file_status symlink_status(path const &dest [,
error_code &ec]))
(when calling tt(symlink_status(dest)) the status of tt(dest) itself is
returned. Thus, if tt(dest) refers to a symlink then
tt(symlink_status) does em(not) return the status of the entry
tt(dest) refers to, but the status of tt(dest) itself: a symbolic link
(with tt(file_status's type()) member returning
tt(file_type::symlink));)
ithtq(status_known)(bool status_known(file_status const &status))
(returns tt(true) if tt(status) refers to a determined status
(tt(status) itself may indicate that the entity referred to by
tt(status) does not exist). One way of receiving tt(false) is by
passing it a default status object: tt(status_known(file_status{}));)
)
Once a tt(file_status) object is obtained the file type of the entry whose
status it represents can be interrogated using these functions (defined in the
tt(filesystem) namespace, where tt(WHATEVER) is the requested
specification):
verb( bool is_WHATEVER(file_status status)
bool is_WHATEVER(path const path &entry [, error_code &ec]))
These functions return tt(true) if tt(status) or tt(status) matches the
requested type. Here are the available functions:
itemization(
iti(is_block_file): the path refers to a block device;
iti(is_character_file): the path refers to a character device;
iti(is_directory): the path refers to a directory;
iti(is_empty): the path refers to an empty file or directory;
iti(is_fifo): the path refers to a named pipe;
iti(is_other): the path does not refer to a directory, regular file or
symlink;
iti(is_regular_file): the path refers to a regular file;
iti(is_socket): the path refers to a named socket;
iti(is_symlink): the path refers to a symbolic link;
)
Alternatively, the tt(file_status::type()) member can be used in, e.g., a
tt(switch) to select an entry matching its tt(file_type) return value (see the
previous section (ref(FSSTATUS)) for a description of the symbols defined by
the tt(file_type) enum).
Here is a little program showing how file statuses can be obtained and
shown (for the em(map) see section ref(MAP)):
verbinsert(-s4 //demo examples/statusknown.cc)
|
