I know this is an old thread, but being the pedant I am I can't resist. None of the examples of the 'right' way to do it are optimal. Remember that m_bUsed is already defined to be a bool. Also notice iHandle is an int, which could be negative. typedef struct { // Lot of stuffs.. bool m_bUsed; } CONFIG; #define MAX_CFG 10 static CONFIG g_vConfigurations[MAX_CFG]; ... bool IsUsed ( int iHandle ) { if (iHandle >= 0 && iHandle < MAX_CFG) return g_vConfigurations[iHandle ].m_bUsed; return false; }