We had a long discussion with ordex about this patch and came to the
conclusion that error printing is currently broken on Windows and
needs a proper fixing.
Why is it broken?
- the bug that my patch fixes - we use Windows's GetLastError to get
Windows last error code and with that strerror to get C runtime error
description
- we have code which uses M_ERRNO to get description of C runtime
errors, for example
int fd = platform_open(filename, O_CREAT | O_TRUNC | O_WRONLY,
S_IRUSR | S_IWUSR);
if (fd == -1)
{
msg(M_ERRNO, "Cannot open file '%s' for write", filename);
return false;
}
but this doesn't really work, because msg(M_ERRNO) uses
GetLastError on Windows to get error code, and C runtime (in above
case it is _wopen) doesn't set the WinAPI's last error code.
- we have code which uses M_ERRNO to print description of socket errors
const ssize_t size = send(sd, buf, strlen(buf), MSG_NOSIGNAL);
if (size != (ssize_t) strlen(buf))
{
msg(D_LINK_ERRORS | M_ERRNO, "send_line: TCP port write failed
on send()");
return false;
}
but in this case we should use WSAGetLastError on Windows and errno on
other platforms.
What we propose:
- M_ERRNO prints only C runtime errors on all platforms and should be
only used with C runtime functions
- We add M_WINERR which uses GetLastError and FormatMessage to print
Windows errors
- We add M_SOCKERR, which is resolved into M_ERRNO on all platforms
except Windows and on Windows it is M_WSAERR. We use WSAGetLastError
and FormatMessage to print WSA errors. Socket functions use M_SOCKERR.
-Lev
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