From Jason Turner

[cpp.pragma.op]

C++14 → C++17 5.1 KB 52 lines
Current Draft | LaTeX Source
Archived: C++14 | C++17
Markdown: C++14 | C++17
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  1. tmp/tmpjus_oiwb/{from.md → to.md} +21 -26
tmp/tmpjus_oiwb/{from.md → to.md} RENAMED
@@ -13,10 +13,12 @@ and replacing each escape sequence `\\` by a single backslash. The
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  resulting sequence of characters is processed through translation phase
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  3 to produce preprocessing tokens that are executed as if they were the
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  *pp-tokens* in a pragma directive. The original four preprocessing
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  tokens in the unary operator expression are removed.
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18
  ``` cpp
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  #pragma listing on "..\listing.dir"
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  ```
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22
  can also be expressed as:
@@ -33,10 +35,12 @@ literally as shown, or results from macro replacement, as in:
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  #define PRAGMA(x) _Pragma(#x)
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  LISTING( ..\listing.dir )
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  ```
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  <!-- Link reference definitions -->
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  [basic.stc.dynamic.safety]: basic.md#basic.stc.dynamic.safety
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  [cpp]: #cpp
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  [cpp.concat]: #cpp.concat
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  [cpp.cond]: #cpp.cond
@@ -52,69 +56,60 @@ LISTING( ..\listing.dir )
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  [cpp.scope]: #cpp.scope
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  [cpp.stringize]: #cpp.stringize
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  [cpp.subst]: #cpp.subst
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  [cstdint]: language.md#cstdint
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  [expr.const]: expr.md#expr.const
 
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  [intro.multithread]: intro.md#intro.multithread
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  [lex.digraph]: lex.md#lex.digraph
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  [lex.name]: lex.md#lex.name
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  [lex.phases]: lex.md#lex.phases
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  [lex.token]: lex.md#lex.token
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  [support.limits]: language.md#support.limits
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- [^1]: Thus, preprocessing directives are commonly called “lines.” These
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  “lines” have no other syntactic significance, as all white space is
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  equivalent except in certain situations during preprocessing (see
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  the `#` character string literal creation operator in 
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  [[cpp.stringize]], for example).
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  [^2]: Because the controlling constant expression is evaluated during
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  translation phase 4, all identifiers either are or are not macro
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  names — there simply are no keywords, enumeration constants, etc.
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- [^3]: An alternative token ([[lex.digraph]]) is not an identifier, even
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- when its spelling consists entirely of letters and underscores.
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- Therefore it is not subject to this replacement.
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-
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- [^4]: Thus on an implementation where `std::numeric_limits<int>::max()`
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- is `0x7FFF` and `std::numeric_limits<unsigned int>::max()` is
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- `0xFFFF`, the integer literal `0x8000` is signed and positive within
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- a `#if` expression even though it is unsigned in translation phase
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- 7 ([[lex.phases]]).
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-
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- [^5]: Thus, the constant expression in the following `#if` directive and
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- `if` statement is not guaranteed to evaluate to the same value in
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- these two contexts.
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-
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- [^6]: As indicated by the syntax, a preprocessing token shall not follow
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  a `#else` or `#endif` directive before the terminating new-line
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  character. However, comments may appear anywhere in a source file,
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  including within a preprocessing directive.
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- [^7]: Note that adjacent string literals are not concatenated into a
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  single string literal (see the translation phases in 
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  [[lex.phases]]); thus, an expansion that results in two string
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  literals is an invalid directive.
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- [^8]: Since, by macro-replacement time, all character literals and
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  string literals are preprocessing tokens, not sequences possibly
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  containing identifier-like subsequences (see [[lex.phases]],
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  translation phases), they are never scanned for macro names or
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  parameters.
103
 
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- [^9]: An alternative token ([[lex.digraph]]) is not an identifier, even
105
  when its spelling consists entirely of letters and underscores.
106
  Therefore it is not possible to define a macro whose name is the
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  same as that of an alternative token.
108
 
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- [^10]: Despite the name, a non-directive is a preprocessing directive.
 
110
 
111
- [^11]: Placemarker preprocessing tokens do not appear in the syntax
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  because they are temporary entities that exist only within
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  translation phase 4.
114
 
115
- [^12]: It is intended that future versions of this standard will replace
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- the value of this macro with a greater value. Non-conforming
117
- compilers should use a value with at most five decimal digits.
 
118
 
119
- [^13]: The presumed source file name and line number can be changed by
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- the `#line` directive.
 
 
 
13
  resulting sequence of characters is processed through translation phase
14
  3 to produce preprocessing tokens that are executed as if they were the
15
  *pp-tokens* in a pragma directive. The original four preprocessing
16
  tokens in the unary operator expression are removed.
17
 
18
+ [*Example 1*:
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+
20
  ``` cpp
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  #pragma listing on "..\listing.dir"
22
  ```
23
 
24
  can also be expressed as:
 
35
  #define PRAGMA(x) _Pragma(#x)
36
 
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  LISTING( ..\listing.dir )
38
  ```
39
 
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+ — *end example*]
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+
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  <!-- Link reference definitions -->
43
  [basic.stc.dynamic.safety]: basic.md#basic.stc.dynamic.safety
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  [cpp]: #cpp
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  [cpp.concat]: #cpp.concat
46
  [cpp.cond]: #cpp.cond
 
56
  [cpp.scope]: #cpp.scope
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  [cpp.stringize]: #cpp.stringize
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  [cpp.subst]: #cpp.subst
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  [cstdint]: language.md#cstdint
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  [expr.const]: expr.md#expr.const
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+ [expr.new]: expr.md#expr.new
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  [intro.multithread]: intro.md#intro.multithread
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  [lex.digraph]: lex.md#lex.digraph
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  [lex.name]: lex.md#lex.name
65
  [lex.phases]: lex.md#lex.phases
66
  [lex.token]: lex.md#lex.token
67
  [support.limits]: language.md#support.limits
68
 
69
+ [^1]: Thus, preprocessing directives are commonly called “lines”. These
70
  “lines” have no other syntactic significance, as all white space is
71
  equivalent except in certain situations during preprocessing (see
72
  the `#` character string literal creation operator in 
73
  [[cpp.stringize]], for example).
74
 
75
  [^2]: Because the controlling constant expression is evaluated during
76
  translation phase 4, all identifiers either are or are not macro
77
  names — there simply are no keywords, enumeration constants, etc.
78
 
79
+ [^3]: As indicated by the syntax, a preprocessing token shall not follow
 
 
 
 
 
 
 
 
 
 
 
 
 
 
80
  a `#else` or `#endif` directive before the terminating new-line
81
  character. However, comments may appear anywhere in a source file,
82
  including within a preprocessing directive.
83
 
84
+ [^4]: Note that adjacent string literals are not concatenated into a
85
  single string literal (see the translation phases in 
86
  [[lex.phases]]); thus, an expansion that results in two string
87
  literals is an invalid directive.
88
 
89
+ [^5]: Since, by macro-replacement time, all character literals and
90
  string literals are preprocessing tokens, not sequences possibly
91
  containing identifier-like subsequences (see [[lex.phases]],
92
  translation phases), they are never scanned for macro names or
93
  parameters.
94
 
95
+ [^6]: An alternative token ([[lex.digraph]]) is not an identifier, even
96
  when its spelling consists entirely of letters and underscores.
97
  Therefore it is not possible to define a macro whose name is the
98
  same as that of an alternative token.
99
 
100
+ [^7]: A *conditionally-supported-directive* is a preprocessing directive
101
+ regardless of whether the implementation supports it.
102
 
103
+ [^8]: Placemarker preprocessing tokens do not appear in the syntax
104
  because they are temporary entities that exist only within
105
  translation phase 4.
106
 
107
+ [^9]: It is intended that future versions of this International Standard
108
+ will replace the value of this macro with a greater value.
109
+ Non-conforming compilers should use a value with at most five
110
+ decimal digits.
111
 
112
+ [^10]: The presumed source file name can be changed by the `#line`
113
+ directive.
114
+
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+ [^11]: The presumed line number can be changed by the `#line` directive.