3 docs tagged with "elf"

Every variable and every function in your firmware ends up in one of about six buckets, and which bucket it lands in is decided by two things: whether it is code or data, and whether its initial value is zero. That is nearly the whole rule. int counter; goes in .bss because its initial value is zero. int counter = 5; goes in .data because it is not. const int limit = 5; goes in .rodata because it never changes and can therefore stay in flash. Nobody chose those placements for your variable; the compiler applied that rule and emitted a section name.

Object files (.o, .obj) are compiled but not yet linked binary files containing machine code, data, and metadata for the linker.

Every firmware project reaches the same afternoon. The build that fitted last week does not fit this week, or it fits but the RAM figure has doubled, and nobody changed anything that should have cost 12 KB. The instinct is to start deleting features. The correct move is to ask the toolchain, which has known the answer the whole time and wrote it down.