3.6.13.1 Short-enums Option

The -fshort-enums option allocates the smallest possible integer type (with a size of 1, 2, or 4 bytes) to an enum such that the range of possible values can be held.

The -fno-short-enums form of this option forces each enum type to be 2-bytes wide (the size of the int type). This is the default action if no option is specified. When using this option, generated code is not binary compatible with code generated without the option.