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/*
* unspcs.c:
* 1998/08 made public kmatsui
*
* These texts are unportable ones, because the order of the evaluation is
* unspecified. Good preprocessor will warn at these texts even if the
* results are valid. Good preprocessor will also document the order of
* evaluation and the behavior on invalid results.
* Note: Order of evaluation of sub-expressions (other than operands of &&,
* ||, ? :) of #if expression is also unspecified. The order, however, never
* affects the result, because #if expression never cause side effect, so no
* warning is necessary. Precedence and grouping rules of operators are other
* things than order of evaluation, and shall be obeyed by preprocessor.
*/
#include "defs.h"
#define str( a) # a
#define xstr( a) str( a)
main( void)
{
/* s.1.1: Order of evaluation of #, ## operators. */
#define MAKWIDESTR( s) L ## # s
/* Either of L"name"; or L# name; ("L#" is not a valid pp-token). */
assert( MAKWIDESTR( name)[ 0] == L'n');
/* s.1.2: Order of evaluation of ## operators. */
#define glue3( a, b, c) a ## b ## c
/* "1.a" or undefined, since .a is not a valid pp-token, while 1. and 1.a are
valid pp-tokens. */
puts( xstr( glue3( 1, ., a)));
return 0;
}
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