Usage Modes

The libc can used in two different modes:

1. The overlay mode: In this mode, the link order semantics are exploited to overlay implementations from LLVM’s libc over the system libc. See Overlay Mode for more information about this mode. In this mode, libc uses the ABI of the system it’s being overlayed onto. Headers are NOT generated. libllvmlibc.a is the only build artifact.

2. The fullbuild mode: In this mode, LLVM’s libc is used as the only libc for the binary. See Fullbuild Mode for information about this mode. In this mode, libc uses its own ABI. Headers are generated along with a libc.a.