setjmp.h functions allow the normal function mechanisms to be bypassed and should be used only with extreme caution, if at all.
Calling setjmp saves the program environment into the buffer passed into the call. Later calling longjmp returns
execution to the point at which setjmp was called and restores the context that was saved into the buffer. But the values of non-volatile
local variables after longjmp are indeterminate. Additionally invoking longjmp from a nested signal handler is undefined, as
is longjmping back to a method that has already completed execution.
This rule flags all instances of setjmp, _setjmp, longjmp, _longjmp, sigsetjmp,
siglongjmp and <setjmp.h>.
Noncompliant code example
#include <setjmp.h> // Noncompliant
jmp_buf buf;
int main(int argc, char* argv[]) {
int i = setjmp(buf); // Noncompliant
if (i == 0) { // value of i was assigned after env was saved & will be indeterminate after longjmp();
// normal execution
} else {
// recover
}
}
//...
void fun() {
//...
longjmp(buf, 1); // Noncompliant
}
Compliant solution
int main(int argc, char* argv[]) {
// normal execution
}
//...
void fun() {
//...
}
