What is -ffreestanding option in gcc?
What is ffreestanding
in gcc ? What is it used for ? I came across the following :
gcc -ffreestanding -m32 -c kernel.c -o kernel.o
and do not understand, what does it mean exactly.
Solution 1:
A freestanding
environment is one in which the standard library may not exist, and program startup may not necessarily be at "main". The option -ffreestanding
directs the compiler to not assume that standard functions have their usual definition.
By default, GCC will act as the compiler for a hosted implementation, defining __STDC_HOSTED__
as 1 and presuming that when the names of ISO C functions are used, they have the semantics defined in the standard. To make it act as a conforming freestanding implementation for a freestanding environment, use the option -ffreestanding
. It will then define __STDC_HOSTED__
to 0, and not make assumptions about the meanings of function names from the standard library.
For more Info, This link may help.