Syntax

__attribute__((visibility("visibility_type")))

Where visibility_type is one of the following:

default

The assumed visibility of symbols can be changed by other options. Default visibility overrides such changes. Default visibility corresponds to external linkage.

hidden

The symbol is not placed into the dynamic symbol table, so no other executable or shared library can directly reference it. Indirect references are possible using function pointers.

protected

The symbol is placed into the dynamic symbol table, but references within the defining module bind to the local symbol. That is, the symbol cannot be overridden by another module.

void __attribute__((visibility("protected"))) foo()
{
   ...
}