API-MS-Win-Core-Fibers-L1-1-0

All functions in the API-MS-Win-Core-Fibers-L1-1-0 set are documented exports from KERNEL32 in version 5.2 and higher:

• FlsAlloc
• FlsFree
• FlsGetValue
• FlsSetValue

The implementations in KERNEL32 version 6.1 and higher are just stubs which transfer the handling to wherever the schema redirects the API Set.

New Locations

Non-trivial implementations of all functions in this API Set are exported from KERNELBASE version 6.1 and higher.

Schema Redirection

The Windows 7 schema redirects this API Set to KERNELBASE. Thus:

• high-level executables, which do not use the API Set, continue to import these functions from KERNEL32;
• low-level executables have their imports from the API Set redirected to KERNELBASE;
• as a particular case of the preceding, the stub implementations in KERNEL32 import from underlying implementations in KERNELBASE.