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| Code Block | ||||
|---|---|---|---|---|
| ||||
#include <signal.h>
#include <stddef.h>
#include <stdlib.h>
volatile sig_atomic_t denom;
void sighandle(int s){
/* Fix the offending volatile. */
if (denom == 0) {
denom = 1;
}
}
int main(int argc, char *argv[]){
int result = 0;
if (argc < 2) {
return 0;
}
denom = (sig_atomic_t)strtol(argv[1], NULL, 10);
signal(SIGFPE,(*sighandle));
result = 100 / (int)denom;
return 0;
}
|
The noncompliant code example will loop infinitely on input 0 when compiled with GCC 4.3 or GCC 3.4. It illustrates that even when a SIGFPE handler attempts to fix the error condition while obeying all other rules of signal handling, the program still does not behave as expected.
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| Code Block | ||||
|---|---|---|---|---|
| ||||
#include <signal.h>
#include <stddef.h>
#include <stdlib.h>
volatile sig_atomic_t denom;
void sighandle(int s){
/* Recovery is impossible. */
abort();
}
int main(int argc, char *argv[]){
int result = 0;
if (argc < 2) {
return 0;
}
denom = (sig_atomic_t)strtol(argv[1], NULL, 10);
signal(SIGFPE,(*sighandle));
result = 100 / (int)denom;
return 0;
}
|
Implementation Details
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