micropython/lib/embed/__errno.c

// This file provides a version of __errno() for embedded systems that do not have one.
// This function is needed for expressions of the form: &errno

static int embed_errno;

#if defined(__linux__)
int *__errno_location(void)
#else
int *__errno(void)
#endif
{
    return &embed_errno;
}
py/stream: Remove mp_stream_errno and use system errno instead. This change is made for two reasons: 1. A 3rd-party library (eg berkeley-db-1.xx, axtls) may use the system provided errno for certain errors, and yet MicroPython stream objects that it calls will be using the internal mp_stream_errno. So if the library returns an error it is not known whether the corresponding errno code is stored in the system errno or mp_stream_errno. Using the system errno in all cases (eg in the mp_stream_posix_XXX wrappers) fixes this ambiguity. 2. For systems that have threading the system-provided errno should always be used because the errno value is thread-local. For systems that do not have an errno, the new lib/embed/__errno.c file is provided. 5 years ago			`// This file provides a version of __errno() for embedded systems that do not have one.`
			`// This function is needed for expressions of the form: &errno`

			`static int embed_errno;`

			`#if defined(__linux__)`
			`int *__errno_location(void)`
			`#else`
			`int *__errno(void)`
			`#endif`
			`{`
			`return &embed_errno;`
			`}`