source: python/vendor/Python-2.7.6/PC/generrmap.c

#include <stdio.h>
#include <errno.h>

/* Extract the mapping of Win32 error codes to errno */

int main()
{
    int i;
    printf("/* Generated file. Do not edit. */\n");
    printf("int winerror_to_errno(int winerror)\n");
    printf("{\n\tswitch(winerror) {\n");
    for(i=1; i < 65000; i++) {
        _dosmaperr(i);
        if (errno == EINVAL)
            continue;
        printf("\t\tcase %d: return %d;\n", i, errno);
    }
    printf("\t\tdefault: return EINVAL;\n");
    printf("\t}\n}\n");
}