A dummy application which prints errno as its first action reveals that errno is non-zero in at least two cases: the application is linked with libthr.so, because the thr_wake(-1) call in _thr_rtld_init() sets errno = ESRCH, and second, the application is statically linked with libthr.a, since libc's uexterr_ctr() runs after the exterrctl(EXTERRCTL_ENABLE) call in init_main_thread(), so the second exterrctl() call returns EBUSY (since it does not specify EXTERRCTLF_FORCE. Just zero errno immediately before program startup. Or, maybe we should be more careful and clear errno in the precise spots where errors can occur? Reported by: Greg Becker
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Buildable 65036 Build 61919: arc lint + arc unit
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Also see D50997.
Note that any constructor could leave errno non-zero, libc and libthr are not more guilty than arbitrary user code there.
From this PoV, the proper test for the issue should include some code like this:
static void f(void) __attribute__((constructor));
static void
f(void)
{
errno = 11;
}Comment Actions
You posted first and your version has a nice comment, so please go ahead and I'll commit the updated tests separately.