/* $NetBSD: c11_generic_expression.c,v 1.13 2022/06/22 19:23:18 rillig Exp $ */ # 3 "c11_generic_expression.c" /* * C99 added support for type-generic macros, but these were limited to the * header . C11 made this feature generally available. * * The generic selection is typically used with macros, but since lint1 works * on the preprocessed source, the test cases look a bit strange. * * C99 6.5.1.1 "Generic selection" */ /* lint1-extra-flags: -Ac11 */ /* * The type of 'var' is not compatible with any of the types from the * generic-association. This is a compile-time error. */ const char * classify_type_without_default(double var) { /* expect-2: warning: argument 'var' unused in function 'classify_type_without_default' [231] */ return _Generic(var, long double: "long double", long long: "long long", unsigned: "unsigned" ); /* expect-1: warning: function 'classify_type_without_default' expects to return value [214] */ } /* * In this case, the 'default' expression is selected. */ const char * classify_type_with_default(double var) { /* expect-2: warning: argument 'var' unused in function 'classify_type_with_default' [231] */ return _Generic(var, long double: "long double", long long: "long long", unsigned: "unsigned", default: "unknown" ); } /* * The type of a _Generic expression is the one from the selected association. */ const char * classify_char(char c) { /* expect-2: warning: argument 'c' unused in function 'classify_char' [231] */ return _Generic(c, char: "yes", default: 0.0 ); } /* * Before cgram.y 1.238 from 2021-06-27, lint accepted a comma-expression, * which looked as if _Generic would accept multiple arguments before the * selection. */ /* ARGSUSED */ const int * comma_expression(char first, double second) { /* expect+1: error: syntax error 'second' [249] */ return _Generic(first, second, char: "first", double: 2.0 ); /* expect+1: warning: function 'comma_expression' falls off bottom without returning value [217] */ } /* * Ensure that assignment-expressions are accepted by the grammar, as * opposed to comma-expressions. */ /* ARGSUSED */ int assignment_expression(int first, int second) { return _Generic(first = second, int: second = first ); } int primary_expression(void) { return _Generic(0, int: assignment_expression)(0, 0); } /* * The types don't match, therefore build_generic_selection returns NULL, * which is then silently ignored by init_expr. This situation is already * covered by the compilers, so there is no need for lint to double-check it. */ const char *x = _Generic( 1ULL + 1.0f, int: 1 );