Function xmlIsMainThread 

#[unsafe(no_mangle)]
pub const unsafe extern "C" fn xmlIsMainThread() -> c_int

Check whether the current thread is the main thread.

UPSTREAM-PARITY

int xmlIsMainThread(void);

SAFETY

The function touches crate-global state only; it is safe as long as the caller respects the library’s global initialization/cleanup ordering (xmlInitParser before use, xmlCleanupParser only after all users are done).

Violating the global lifecycle ordering, or calling this after teardown or from a signal handler, is undefined behavior.