Determines whether the compiler treats common symbols as global definitions.
- The compiler does not treat common symbols as global definitions.
This option determines whether the compiler treats common symbols as global definitions and to allocate memory for each symbol at compile time.
-fno-commontells the compiler to treat common symbols as global definitions. When using this option, you can only have a common variable declared in one module; otherwise, a link time error will occur for multiple defined symbols.
Normally, a file-scope declaration with no initializer and without the
statickeyword "int i;" is represented as a common symbol. Such a symbol is treated as an external reference. However, if no other compilation unit has a global definition for the name, the linker allocates memory for it.