From Jason Turner

[fs.path.cvt]

C++17 → C++20 6.0 KB 61 lines
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@@ -1,12 +1,12 @@
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- #### `path` conversions <a id="fs.path.cvt">[[fs.path.cvt]]</a>
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- ##### `path` argument format conversions <a id="fs.path.fmt.cvt">[[fs.path.fmt.cvt]]</a>
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  [*Note 1*:
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- The format conversions described in this section are not applied on
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  POSIX-based operating systems because on these systems:
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  - The generic format is acceptable as a native path.
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  - There is no need to distinguish between native format and generic
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  format in function arguments.
@@ -15,15 +15,15 @@ POSIX-based operating systems because on these systems:
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  — *end note*]
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  Several functions are defined to accept *detected-format* arguments,
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  which are character sequences. A detected-format argument represents a
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- path using either a pathname in the generic format (
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- [[fs.path.generic]]) or a pathname in the native format (
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- [[fs.def.native]]). Such an argument is taken to be in the generic
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- format if and only if it matches the generic format and is not
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- acceptable to the operating system as a native path.
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  [*Note 2*: Some operating systems may have no unambiguous way to
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  distinguish between native format and generic format arguments. This is
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  by design as it simplifies use for operating systems that do not require
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  disambiguation. An implementation for an operating system where
@@ -42,12 +42,12 @@ native-to-generic and generic-to-native formats respectively. If
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  If the native format requires paths for regular files to be formatted
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  differently from paths for directories, the path shall be treated as a
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  directory path if its last element is a *directory-separator*, otherwise
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  it shall be treated as a path to a regular file.
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- [*Note 4*: A path stores a native format pathname (
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- [[fs.path.native.obs]]) and acts as if it also stores a generic format
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  pathname, related as given below. The implementation may generate the
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  generic format pathname based on the native format pathname (and
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  possibly other information) when requested. — *end note*]
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  When a path is constructed from or is assigned a single representation
@@ -60,36 +60,43 @@ the other representation. The value *q* converts to *p* (by *G* or *N*
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  as appropriate) if any such value does so; *q* is otherwise unspecified.
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  [*Note 5*: If *q* is the result of converting any path at all, it is
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  the result of converting *p*. — *end note*]
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- ##### `path` type and encoding conversions <a id="fs.path.type.cvt">[[fs.path.type.cvt]]</a>
 
 
 
 
 
 
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  For member function arguments that take character sequences representing
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  paths and for member functions returning strings, value type and
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  encoding conversion is performed if the value type of the argument or
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  return value differs from `path::value_type`. For the argument or return
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  value, the method of conversion and the encoding to be converted to is
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  determined by its value type:
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- - `char`: The encoding is the native narrow encoding (
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- [[fs.def.native.encode]]). The method of conversion, if any, is
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- operating system dependent. \[*Note 6*: For POSIX-based operating
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- systems `path::value_type` is `char` so no conversion from `char`
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- value type arguments or to `char` value type return values is
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- performed. For Windows-based operating systems, the native narrow
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- encoding is determined by calling a Windows API
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  function. — *end note*] \[*Note 7*: This results in behavior
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  identical to other C and C++ standard library functions that perform
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- file operations using narrow character strings to identify paths.
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  Changing this behavior would be surprising and error
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  prone. — *end note*]
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- - `wchar_t`: The encoding is the native wide encoding (
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- [[fs.def.native.encode]]). The method of conversion is unspecified.
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- \[*Note 8*: For Windows-based operating systems `path::value_type` is
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- `wchar_t` so no conversion from `wchar_t` value type arguments or to
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- `wchar_t` value type return values is performed. — *end note*]
 
 
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  - `char16_t`: The encoding is UTF-16. The method of conversion is
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  unspecified.
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  - `char32_t`: The encoding is UTF-32. The method of conversion is
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  unspecified.
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+ #### Conversions <a id="fs.path.cvt">[[fs.path.cvt]]</a>
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+ ##### Argument format conversions <a id="fs.path.fmt.cvt">[[fs.path.fmt.cvt]]</a>
4
 
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  [*Note 1*:
6
 
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+ The format conversions described in this subclause are not applied on
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  POSIX-based operating systems because on these systems:
9
 
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  - The generic format is acceptable as a native path.
11
  - There is no need to distinguish between native format and generic
12
  format in function arguments.
 
15
 
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  — *end note*]
17
 
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  Several functions are defined to accept *detected-format* arguments,
19
  which are character sequences. A detected-format argument represents a
20
+ path using either a pathname in the generic format [[fs.path.generic]]
21
+ or a pathname in the native format [[fs.class.path]]. Such an argument
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+ is taken to be in the generic format if and only if it matches the
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+ generic format and is not acceptable to the operating system as a native
24
+ path.
25
 
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  [*Note 2*: Some operating systems may have no unambiguous way to
27
  distinguish between native format and generic format arguments. This is
28
  by design as it simplifies use for operating systems that do not require
29
  disambiguation. An implementation for an operating system where
 
42
  If the native format requires paths for regular files to be formatted
43
  differently from paths for directories, the path shall be treated as a
44
  directory path if its last element is a *directory-separator*, otherwise
45
  it shall be treated as a path to a regular file.
46
 
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+ [*Note 4*: A path stores a native format pathname
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+ [[fs.path.native.obs]] and acts as if it also stores a generic format
49
  pathname, related as given below. The implementation may generate the
50
  generic format pathname based on the native format pathname (and
51
  possibly other information) when requested. — *end note*]
52
 
53
  When a path is constructed from or is assigned a single representation
 
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  as appropriate) if any such value does so; *q* is otherwise unspecified.
61
 
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  [*Note 5*: If *q* is the result of converting any path at all, it is
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  the result of converting *p*. — *end note*]
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+ ##### Type and encoding conversions <a id="fs.path.type.cvt">[[fs.path.type.cvt]]</a>
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+
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+ The *native encoding* of an ordinary character string is the operating
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+ system dependent current encoding for pathnames [[fs.class.path]]. The
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+ *native encoding* for wide character strings is the
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+ implementation-defined execution wide-character set encoding
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+ [[lex.charset]].
72
 
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  For member function arguments that take character sequences representing
74
  paths and for member functions returning strings, value type and
75
  encoding conversion is performed if the value type of the argument or
76
  return value differs from `path::value_type`. For the argument or return
77
  value, the method of conversion and the encoding to be converted to is
78
  determined by its value type:
79
 
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+ - `char`: The encoding is the native ordinary encoding. The method of
81
+ conversion, if any, is operating system dependent. \[*Note 6*: For
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+ POSIX-based operating systems `path::value_type` is `char` so no
83
+ conversion from `char` value type arguments or to `char` value type
84
+ return values is performed. For Windows-based operating systems, the
85
+ native ordinary encoding is determined by calling a Windows API
 
86
  function. — *end note*] \[*Note 7*: This results in behavior
87
  identical to other C and C++ standard library functions that perform
88
+ file operations using ordinary character strings to identify paths.
89
  Changing this behavior would be surprising and error
90
  prone. — *end note*]
91
+ - `wchar_t`: The encoding is the native wide encoding. The method of
92
+ conversion is unspecified. \[*Note 8*: For Windows-based operating
93
+ systems `path::value_type` is `wchar_t` so no conversion from
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+ `wchar_t` value type arguments or to `wchar_t` value type return
95
+ values is performed. — *end note*]
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+ - `char8_t`: The encoding is UTF-8. The method of conversion is
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+ unspecified.
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  - `char16_t`: The encoding is UTF-16. The method of conversion is
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  unspecified.
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  - `char32_t`: The encoding is UTF-32. The method of conversion is
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  unspecified.
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