1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 | #include <stdio.h>
#include <stdlib.h>
void foo(int* a_n) { // set value *at* a_n to 5
*a_n = 5;
// Okay for foo(…) to write to main(…)'s stack frame
// i.e., if main passes the address of one if its local
// variables. However, if foo(…) returned the address
// of something in its stack frame, main(…) should
// not touch it.
}
int main(int argc, char* argv[]) {
int n = 0;
printf("Before: n == %d\n", n);
foo(&n); // pass the address of n to foo(…)
printf("After: n == %d\n", n);
/* Before: n == 0
* After: n == 5
*/
return EXIT_SUCCESS;
}
/* vim: set tabstop=4 shiftwidth=4 fileencoding=utf-8 noexpandtab: */
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