Re: [Bug-glpk] misc/wclique1.c:121:7: warning: 'memset': specified size between 18446744071562067968 and 18446744073709551615 exceeds maximum object size 9223372036854775807 [-Wstringop-overflow=]

[Andrew Makhorin]

Hi Heinrich,

> 
> when compiling GLPK-4.64 with GCC 7.2 the following warning is shown:
> 
> misc/wclique1.c: In function '_glp_wclique1':
> misc/wclique1.c:121:7: warning: 'memset': specified size between 
> 18446744071562067968 and 18446744073709551615 exceeds maximum object 
> size 9223372036854775807 [-Wstringop-overflow=]
>         memset(&skip[1], 0, sizeof(char) * n);
>         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> misc/wclique1.c:123:7: warning: 'memset': specified size between 
> 18446744071562067968 and 18446744073709551615 exceeds maximum object 
> size 9223372036854775807 [-Wstringop-overflow=]
>         memset(&d_flag[1], 0, sizeof(char) * n);
> 

Please ignore these warnings. They appear because n being declared as
int is converted to sizeof type which is unsigned long64. However, n
cannot be negative due to a precondition xassert(n >= 0) above. (GCC as
well as many other C compilers want to be smarter than they actually
are.)

Best,

Andrew Makhorin