# C compiler selection

For ordinary C builds without `-cc`, V uses an available TinyCC when the target and build
options allow it. For binary output, V checks native flags and probes link dependencies before
transforming or monomorphizing the program. Known incompatible C++ or Objective-C inputs, external
objects on macOS, and missing or incompatible dependencies select the platform compiler.
Deferred compile-time branches are excluded from this probe until their conditions are known.
C and object output skip the link dependency probe.

If headers or generated program symbols expose a later TinyCC failure, V regenerates the program
for the platform compiler. Regeneration re-evaluates compiler-specific conditions such as
`$if tinyc`. On POSIX systems it replaces the compiler process, releasing the earlier AST and C
buffers before the retry. Windows waits for the retry to preserve its exit status.

Known incompatible native inputs select the platform compiler quietly; `-v` reports the reason.
Dependency probe failures and later TinyCC failures print a warning after semantic validation.
Invalid programs retain their existing error diagnostics. `-silent` suppresses this warning.
An explicit `-cc tcc` bypasses early preflight and retains the existing
retry behavior for recognized TinyCC failures. `-no-retry-compilation` disables these retries.
Passing `-cc clang`, `-cc gcc`, or `-cc cc` selects that compiler directly.