1 // Check that a qsort() comparator that calls qsort() works as expected
2 // RUN: %clangxx -O2 %s -o %t
3 // RUN: %run %t 2>&1 | FileCheck %s
4 
5 #include <stdio.h>
6 #include <stdlib.h>
7 
8 struct Foo {
9   int array[2];
10 };
11 int global_array[12] = {7, 11, 9, 10, 1, 2, 4, 3, 6, 5, 8, 12};
12 
13 #define array_size(x) (sizeof(x) / sizeof(x[0]))
14 
15 int ascending_compare_ints(const void *a, const void *b) {
16   return *(const int *)a - *(const int *)b;
17 }
18 
19 int descending_compare_ints(const void *a, const void *b) {
20   // Add another qsort() call to check more than one level of recursion
21   qsort(global_array, array_size(global_array), sizeof(int), &ascending_compare_ints);
22   return *(const int *)b - *(const int *)a;
23 }
24 
25 int sort_and_compare(const void *a, const void *b) {
26   struct Foo *f1 = (struct Foo *)a;
27   struct Foo *f2 = (struct Foo *)b;
28   printf("sort_and_compare({%d, %d}, {%d, %d})\n", f1->array[0], f1->array[1],
29          f2->array[0], f2->array[1]);
30   // Call qsort from within qsort() to check that interceptors handle this case:
31   qsort(&f1->array, array_size(f1->array), sizeof(int), &descending_compare_ints);
32   qsort(&f2->array, array_size(f2->array), sizeof(int), &descending_compare_ints);
33   // Sort by second array element:
34   return f1->array[1] - f2->array[1];
35 }
36 
37 int main() {
38   // Note: 16 elements should be large enough to trigger a recursive qsort() call.
39   struct Foo qsortArg[16] = {
40       {1, 99},
41       {2, 3},
42       {17, 5},
43       {8, 6},
44       {11, 4},
45       {3, 3},
46       {16, 17},
47       {7, 9},
48       {21, 12},
49       {32, 23},
50       {13, 8},
51       {99, 98},
52       {41, 42},
53       {42, 43},
54       {44, 45},
55       {0, 1},
56   };
57   // Sort the individual arrays in descending order and the over all struct
58   // Foo array in ascending order of the second array element.
59   qsort(qsortArg, array_size(qsortArg), sizeof(qsortArg[0]), &sort_and_compare);
60 
61   printf("Sorted result:");
62   for (const auto &f : qsortArg) {
63     printf(" {%d,%d}", f.array[0], f.array[1]);
64   }
65   printf("\n");
66   // CHECK: Sorted result: {1,0} {99,1} {3,2} {3,3} {11,4} {17,5} {8,6} {9,7} {13,8} {21,12} {17,16} {32,23} {42,41} {43,42} {45,44} {99,98}
67   printf("Sorted global_array:");
68   for (int i : global_array) {
69     printf(" %d", i);
70   }
71   printf("\n");
72   // CHECK: Sorted global_array: 1 2 3 4 5 6 7 8 9 10 11 12
73 }
74