http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51834
Bug #: 51834
Summary: -Wsequence-point fails when convoluted expressions
with multiple side effects are used
Classification: Unclassified
Product: gcc
Version: 4.4.6
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: prasoonsaurav....@gmail.com
Consider the following example
int main()
{
int i=10;
i += (i , i++, i) + i; // also invokes UB
}
prasoon@Prasoon:~/test_code$ cat ub.c
int main()
{
int i=10;
i += (i , i++, i) + i; // also invokes UB
}
prasoon@Prasoon:~/test_code$ gcc -Wsequence-point ub.c
prasoon@Prasoon:~/test_code$
I don't get any warning like 'operation on 'i' may be undefined.
Another similar example
int main()
{
char *str;
char array[100]= "Hello";
if((str = array)[0] == 'H'){
//do something
}
}
As per my understanding (str = array)[0] also invokes UB but no warning is
given by gcc even after using that option.
