Warning

If you intend to allow a client to override a function in a library, you must be sure that the function is not generated inline during the library build. The compiler inlines a function if you specify the function name with -xinline, if you compile at -xO4 or higher in which case inlining can happen automatically, if you use the inline specifier, or if you are using cross-file optimization.

For example, suppose library ABC has a default allocator function that can be used by library clients, and is also used internally in the library:

void* ABC_allocator(size_t size) { return malloc(size); }

If you build the library at -xO4 or higher, the compiler inlines calls to ABC_allocator that occur in library components. If a library client wants to replace ABC_allocator with a customized version, the replacement will not occur in library components that called ABC_allocator. The final program will include different versions of the function.

Library functions declared with the __hidden or __symbolic specifiers can be generated inline when building the library. They are not supposed to be overridden by clients. See 4.1 Linker Scoping.

Library functions declared with the __global specifier, should not be declared inline, and should be protected from inlining by use of the -xinline compiler option.