Print errno and strerror in POSIX transport to see better error messages #2373
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| @@ -59,7 +59,9 @@ void FilePOSIX::Open(const std::string &name, const Mode openMode, | |||
| { | |||
| auto lf_AsyncOpenWrite = [&](const std::string &name) -> int { | |||
| ProfilerStart("open"); | |||
| errno = 0; | |||
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I'm confused about this. You set errno to zero, then assign m_Errno to errno, without any intervening assignments. So m_Errno is always zero.
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Oh wow I just read about errno; I guess it behaves like an eflags register.
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There is an intervening system function call that sets 'errno' to non-zero if there is an error. It's standard practice (for C programmers at least) to zero out errno before system calls to not catch errors from the past, hence the errno=0 statement here. m_Errno is used to remember the (possible) error for the call right after this and checked later (possibly the call in happens in a thread, line 63, but the check is in main thread much later)
-- don't know what is happening on the NVMe