[Bug-glpk] -Wstringop-overflow in function _glp_wclique1

[Heinrich Schuchardt]

Hello Andrew,

compiling GLPK 4.63 on arm64 with gcc 7.2 gives the following warning:

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);
       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

It can be avoided by first converting to unsigned int:

120       /* initially all vertices are unmarked */
121       memset(&skip[1], 0, sizeof(char) * (unsigned int)n);
122       /* clear flags of all vertices */
123       memset(&d_flag[1], 0, sizeof(char) * (unsigned int)n);

Best regards

Heinrich Schuchardt