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queries.c revision 1.1 
      1 /*	$NetBSD: queries.c,v 1.1 2022/07/05 22:50:41 rillig Exp $	*/
      2 # 3 "queries.c"
      3 
      4 /*
      5  * Demonstrate the case-by-case queries.  Unlike warnings, queries do not
      6  * point to questionable code but rather to code that may be interesting to
      7  * inspect manually on a case-by-case basis.
      8  *
      9  * Possible use cases are:
     10  *
     11  *	Understanding how C works internally, by making the usual arithmetic
     12  *	conversions visible.
     13  *
     14  * 	Finding code that intentionally suppresses a regular lint warning,
     15  * 	such as casts between arithmetic types.
     16  */
     17 
     18 /* lint1-extra-flags: -q 1,2,3,4,5,6,7 */
     19 
     20 int
     21 Q1(double dbl)
     22 {
     23 	/* expect+1: implicit conversion from floating point 'double' to integer 'int' [Q1] */
     24 	return dbl;
     25 }
     26 
     27 int
     28 Q2(double dbl)
     29 {
     30 	/* expect+2: cast from floating point 'double' to integer 'int' [Q2] */
     31 	/* expect+1: redundant cast from 'double' to 'int' before assignment [Q7] */
     32 	return (int)dbl;
     33 }
     34 
     35 void
     36 Q3(int i, unsigned u)
     37 {
     38 	/* expect+1: implicit conversion changes sign from 'int' to 'unsigned int' [Q3] */
     39 	u = i;
     40 
     41 	/* expect+1: implicit conversion changes sign from 'unsigned int' to 'int' [Q3] */
     42 	i = u;
     43 }
     44 
     45 unsigned long long
     46 Q4(char *ptr, int i, unsigned long long ull)
     47 {
     48 	/*
     49 	 * The conversion from 'char' to 'int' is done by the integer
     50 	 * promotions (C11 6.3.1.1p2), not by the usual arithmetic
     51 	 * conversions (C11 6.3.1.8p1).
     52 	 */
     53 	/* expect+2: usual arithmetic conversion for '+' from 'int' to 'unsigned long long' [Q4] */
     54 	/* expect+1: implicit conversion changes sign from 'int' to 'unsigned long long' [Q3] */
     55 	return ptr[0] + ptr[1] + i + ull;
     56 }
     57 
     58 void
     59 Q5(char *ptr, int i)
     60 {
     61 	if (ptr + i > ptr)
     62 		return;
     63 
     64 	/* expect+1: pointer addition has integer on the left-hand side [Q5] */
     65 	if (i + ptr > ptr)
     66 		return;
     67 
     68 	if (ptr[i] != '\0')
     69 		return;
     70 
     71 	/* expect+1: pointer addition has integer on the left-hand side [Q5] */
     72 	if (i[ptr] != '\0')
     73 		return;
     74 }
     75 
     76 void
     77 Q6(int i)
     78 {
     79 	/* expect+1: no-op cast from 'int' to 'int' [Q6] */
     80 	i = (int)4;
     81 
     82 	/* expect+1: no-op cast from 'int' to 'int' [Q6] */
     83 	i = (int)i + 1;
     84 }
     85 
     86 extern void *allocate(unsigned long);
     87 
     88 char *
     89 Q7(void)
     90 {
     91 	/* expect+1: redundant cast from 'pointer to void' to 'pointer to char' before assignment [Q7] */
     92 	char *str = (char *)allocate(64);
     93 
     94 	if (str == (void *)0)
     95 		/* expect+1: redundant cast from 'pointer to void' to 'pointer to char' before assignment [Q7] */
     96 		str = (char *)allocate(64);
     97 
     98 	return str;
     99 }
    100 
    101 
    102 /*
    103  * Since queries do not affect the exit status, force a warning to make this
    104  * test conform to the general expectation that a test that produces output
    105  * exits non-successfully.
    106  */
    107 /* expect+1: warning: static variable 'unused' unused [226] */
    108 static int unused;
    109