gcc/testsuite/gcc.dg/attr-warn-unused-result.c

   1 /* warn_unused_result attribute tests.  */
   2 /* { dg-do compile } */
   3 /* { dg-options "-O" } */
   4
   5 #define WUR __attribute__((warn_unused_result))
   6 #define WURAI __attribute__((warn_unused_result, always_inline)) inline
   7 typedef WUR int (*fnt) (void);
   8
   9 typedef struct { long i; } A;
  10 typedef struct { long i; long j; } B;
  11 typedef struct { char big[1024]; fnt fn; } C;
  12
  13 WUR int check1 (void);
  14 WUR void check2 (void); /* { dg-warning "attribute ignored" } */
  15 int foo WUR;      /* { dg-warning "only applies" } */
  16 int bar (void);
  17 extern WURAI int check3 (void) { return bar (); }
  18 WUR A check4 (void);
  19 WUR B check5 (void);
  20 WUR C check6 (void);
  21 A bar7 (void);
  22 B bar8 (void);
  23 C bar9 (void);
  24 extern WURAI A check7 (void) { return bar7 (); }
  25 extern WURAI B check8 (void) { return bar8 (); }
  26 extern WURAI C check9 (void) { return bar9 (); }
  27 /* This is useful for checking whether return value of statement
  28    expressions (returning int in this case) is used.  */
  29 extern WURAI int check_int_result (int res) { return res; }
  30 #define GU(v) ({ int e = 0; (v) = bar (); if ((v) < 23) e = 14; e; })
  31 fnt fnptr;
  32 WUR int check10 (void);
  33 int baz (void);
  34 extern WURAI int check11 (void) { return baz (); }
  35 int k;
  36
  37 void
  38 test (void)
  39 {
  40   int i = 0, j;
  41   const fnt pcheck1 = check1;
  42   const fnt pcheck3 = check3;
  43   A a;
  44   B b;
  45   C c;
  46   if (check1 ())
  47     return;
  48   i += check1 ();
  49   i += ({ check1 (); });
  50   check1 ();            /* { dg-warning "ignoring return value of" } */
  51   (void) check1 ();     /* { dg-warning "ignoring return value of" } */
  52   check1 (), bar ();    /* { dg-warning "ignoring return value of" } */
  53   check2 ();
  54   (void) check2 ();
  55   check2 (), bar ();
  56   if (check3 ())
  57     return;
  58   i += check3 ();
  59   i += ({ check3 (); });
  60   check3 ();            /* { dg-warning "ignoring return value of" } */
  61   (void) check3 ();     /* { dg-warning "ignoring return value of" } */
  62   check3 (), bar ();    /* { dg-warning "ignoring return value of" } */
  63   a = check4 ();
  64   if (a.i)
  65     return;
  66   if (check4 ().i)
  67     return;
  68   if (({ check4 (); }).i)
  69     return;
  70   check4 ();            /* { dg-warning "ignoring return value of" } */
  71   (void) check4 ();     /* { dg-warning "ignoring return value of" } */
  72   check4 (), bar ();    /* { dg-warning "ignoring return value of" } */
  73   b = check5 ();
  74   if (b.i + b.j)
  75     return;
  76   if (check5 ().j)
  77     return;
  78   if (({ check5 (); }).j)
  79     return;
  80   check5 ();            /* { dg-warning "ignoring return value of" } */
  81   (void) check5 ();     /* { dg-warning "ignoring return value of" } */
  82   check5 (), bar ();    /* { dg-warning "ignoring return value of" } */
  83   c = check6 ();
  84   if (c.big[12] + c.big[29])
  85     return;
  86   if (check6 ().big[27])
  87     return;
  88   if (({ check6 (); }).big[0])
  89     return;
  90   check6 ();            /* { dg-warning "ignoring return value of" } */
  91   (void) check6 ();     /* { dg-warning "ignoring return value of" } */
  92   check6 (), bar ();    /* { dg-warning "ignoring return value of" } */
  93   a = check7 ();
  94   if (a.i)
  95     return;
  96   if (check7 ().i)
  97     return;
  98   if (({ check7 (); }).i)
  99     return;
 100   check7 ();            /* { dg-warning "ignoring return value of" } */
 101   (void) check7 ();     /* { dg-warning "ignoring return value of" } */
 102   check7 (), bar ();    /* { dg-warning "ignoring return value of" } */
 103   b = check8 ();
 104   if (b.i + b.j)
 105     return;
 106   if (check8 ().j)
 107     return;
 108   if (({ check8 (); }).j)
 109     return;
 110   check8 ();            /* { dg-warning "ignoring return value of" } */
 111   (void) check8 ();     /* { dg-warning "ignoring return value of" } */
 112   check8 (), bar ();    /* { dg-warning "ignoring return value of" } */
 113   c = check9 ();
 114   if (c.big[12] + c.big[29])
 115     return;
 116   if (check9 ().big[27])
 117     return;
 118   if (({ check9 (); }).big[0])
 119     return;
 120   check9 ();            /* { dg-warning "ignoring return value of" } */
 121   (void) check9 ();     /* { dg-warning "ignoring return value of" } */
 122   check9 (), bar ();    /* { dg-warning "ignoring return value of" } */
 123   if (check_int_result (GU (j)))
 124     return;
 125   i += check_int_result (GU (j));
 126   i += ({ check_int_result (GU (j)); });
 127   check_int_result (GU (j)); /* { dg-warning "ignoring return value of" } */
 128   (void) check_int_result (GU (j)); /* { dg-warning "ignoring return value of" } */
 129   check_int_result (GU (j)), bar (); /* { dg-warning "ignoring return value of" } */
 130   if (fnptr ())
 131     return;
 132   i += fnptr ();
 133   i += ({ fnptr (); });
 134   fnptr ();             /* { dg-warning "ignoring return value of" } */
 135   (void) fnptr ();      /* { dg-warning "ignoring return value of" } */
 136   fnptr (), bar ();     /* { dg-warning "ignoring return value of" } */
 137   fnptr = check1;
 138   if (fnptr ())
 139     return;
 140   i += fnptr ();
 141   i += ({ fnptr (); });
 142   fnptr ();             /* { dg-warning "ignoring return value of" } */
 143   (void) fnptr ();      /* { dg-warning "ignoring return value of" } */
 144   fnptr (), bar ();     /* { dg-warning "ignoring return value of" } */
 145   fnptr = check3;
 146   if (fnptr ())
 147     return;
 148   i += fnptr ();
 149   i += ({ fnptr (); });
 150   fnptr ();             /* { dg-warning "ignoring return value of" } */
 151   (void) fnptr ();      /* { dg-warning "ignoring return value of" } */
 152   fnptr (), bar ();     /* { dg-warning "ignoring return value of" } */
 153   if (bar9 ().fn ())
 154     return;
 155   i += bar9 ().fn ();
 156   i += ({ bar9 ().fn (); });
 157   bar9 ().fn ();        /* { dg-warning "ignoring return value of" } */
 158   (void) bar9 ().fn (); /* { dg-warning "ignoring return value of" } */
 159   bar9 ().fn (), bar (); /* { dg-warning "ignoring return value of" } */
 160   if ((k ? check1 : check10) ())
 161     return;
 162   i += (k ? check1 : check10) ();
 163   i += ({ (k ? check1 : check10) (); });
 164   (k ? check1 : check10) (); /* { dg-warning "ignoring return value of" } */
 165   (void) (k ? check1 : check10) (); /* { dg-warning "ignoring return value of" } */
 166   (k ? check1 : check10) (), bar (); /* { dg-warning "ignoring return value of" } */
 167   if ((k ? check3 : check11) ())
 168     return;
 169   i += (k ? check3 : check11) ();
 170   i += ({ (k ? check3 : check11) (); });
 171   (k ? check3 : check11) (); /* { dg-warning "ignoring return value of" } */
 172   (void) (k ? check3 : check11) (); /* { dg-warning "ignoring return value of" } */
 173   (k ? check3 : check11) (), bar (); /* { dg-warning "ignoring return value of" } */
 174   if (pcheck1 ())
 175     return;
 176   i += pcheck1 ();
 177   i += ({ pcheck1 (); });
 178   pcheck1 ();           /* { dg-warning "ignoring return value of" } */
 179   (void) pcheck1 ();    /* { dg-warning "ignoring return value of" } */
 180   pcheck1 (), bar ();   /* { dg-warning "ignoring return value of" } */
 181   if (pcheck3 ())
 182     return;
 183   i += pcheck3 ();
 184   i += ({ pcheck3 (); });
 185   pcheck3 ();           /* { dg-warning "ignoring return value of" } */
 186   (void) pcheck3 ();    /* { dg-warning "ignoring return value of" } */
 187   pcheck3 (), bar ();   /* { dg-warning "ignoring return value of" } */
 188 }