cppdraft_translate/cppdraft/cpp/pragma/op.md

[cpp.pragma.op]

15 Preprocessing directives [cpp]

15.13 Pragma operator [cpp.pragma.op]

1

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A unary operator expression of the form:

_Pragma ( string-literal )

is processed as follows: The string-literal is destringized by deleting the L prefix, if present, deleting the leading and trailing double-quotes, replacing each escape sequence " by a double-quote, and replacing each escape sequence \ by a single backslash.

The resulting sequence of characters is processed through translation phase 3 to produce preprocessing tokens that are executed as if they were thepp-tokens in a pragma directive.

The original four preprocessing tokens in the unary operator expression are removed.

2

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[Example 1:

#pragma listing on "..\listing.dir" can also be expressed as:_Pragma ( "listing on "..\listing.dir"" )

The latter form is processed in the same way whether it appears literally as shown, or results from macro replacement, as in:#define LISTING(x) PRAGMA(listing on #x)#define PRAGMA(x) _Pragma(#x) LISTING( ..\listing.dir )

— end example]