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thanks for the tips! One interesting use of sizeof i remember in my C++ project was to override new and delete operators where a void pointer is passed and siz

thanks for the tips! One interesting use of sizeof i remember in my C++ project was to override new and delete operators where a void pointer is passed and sizeof is used to keep track of how much memory is allocated/deallocated.

pietrofmaggi 16y ago
One interesting usage of sizeof() is to calculate the dimension of an array at compile time: #define dim(x) (sizeof(x) / sizeof(x[0])) and this is handy for static arrays with dimension defined by its data, likes: static const struct { someEnum_t enCommand; void (*Fxn)(stCommands_t *a_psCommand); } m_stCmdMap[] = { {CMD_SD_FREESPACE, _sdFreeSpace}, {CMD_SD_DISK_INFO, _sdDiskInfo}, {CMD_SD_FORMAT, _sdFormat}, } When you add a new array elements, it just keep the stuffs going calculating it at any recompilation: for (i=0; i<dim(m_stCmdMap); i++) { if (m_stCmdMap[i].enCommand == stCmdLocal.enCommand) { m_stCmdMap[i].Fxn(&stCmdCopy); break; } } Another useful macro to work with structs is offsetof(), its incredibly usefull when you have to port some code to different compilers/target with different alignments and paddings.