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| Code Block | ||||
|---|---|---|---|---|
| ||||
void f(int n, int * restrict p, int * restrict q) {
while (n-- > 0)
*p++ = *q++;
}
void g(void) {
extern int d[100];
/* ... */
f(50, d + 50, d); /* valid defined behavior */
} |
Noncompliant Code Example
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| Code Block | ||||
|---|---|---|---|---|
| ||||
void h(size_t n, int * restrict p, int * restrict q, int * restrict r) {
for (size_t i = 0; i < n; i++)
p[i] = q[i] + r[i];
}
void j(void) {
int a[100];
h(100, a, a, a); /* undefined behavior */
} |
The function g() declares an array d consisting of 100 int values and then invokes f() to copy memory from one area of the array to another. This call has undefined behavior because each of d[1] through d[49] is accessed through both p and q .
...
| Code Block | ||||
|---|---|---|---|---|
| ||||
void h(size_t n, int * restrict p, int * restrict q, int * restrict r) {
for (size_t i = 0; i < n; i++)
p[i] = q[i] + r[i];
}
void j(void) {
int a[100];
int b[100];
h(100, a, b, b); /* valid defined behavior */
} |
Invoking Library Functions with restrict-qualified Pointers
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