diff --git a/reactos/lib/sdk/crt/process/process.c b/reactos/lib/sdk/crt/process/process.c
index 1fe8dfbc546..3ae9642bc00 100644
--- a/reactos/lib/sdk/crt/process/process.c
+++ b/reactos/lib/sdk/crt/process/process.c
@@ -296,7 +296,7 @@ do_spawnT(int mode, const _TCHAR* cmdname, const _TCHAR* args, const _TCHAR* env
    {
       dwError = GetLastError();
       ERR("%x\n", dwError);
-      __set_errno(dwError);
+      _dosmaperr(dwError);
       return(-1);
    }
    CloseHandle(ProcessInformation.hThread);
diff --git a/reactos/lib/sdk/crt/stdio/file.c b/reactos/lib/sdk/crt/stdio/file.c
index 98e3cd3df3f..ffa894f8d5e 100644
--- a/reactos/lib/sdk/crt/stdio/file.c
+++ b/reactos/lib/sdk/crt/stdio/file.c
@@ -463,12 +463,12 @@ int CDECL _access(const char *filename, int mode)
 
   if (!filename || attr == INVALID_FILE_ATTRIBUTES)
   {
-    __set_errno(GetLastError());
+    _dosmaperr(GetLastError());
     return -1;
   }
   if ((attr & FILE_ATTRIBUTE_READONLY) && (mode & W_OK))
   {
-    __set_errno(ERROR_ACCESS_DENIED);
+    _dosmaperr(ERROR_ACCESS_DENIED);
     return -1;
   }
   return 0;
@@ -485,12 +485,12 @@ int CDECL _waccess(const wchar_t *filename, int mode)
 
   if (!filename || attr == INVALID_FILE_ATTRIBUTES)
   {
-    __set_errno(GetLastError());
+    _dosmaperr(GetLastError());
     return -1;
   }
   if ((attr & FILE_ATTRIBUTE_READONLY) && (mode & W_OK))
   {
-    __set_errno(ERROR_ACCESS_DENIED);
+    _dosmaperr(ERROR_ACCESS_DENIED);
     return -1;
   }
   return 0;
@@ -511,7 +511,7 @@ int CDECL _chmod(const char *path, int flags)
     if (newFlags == oldFlags || SetFileAttributesA(path, newFlags))
       return 0;
   }
-  __set_errno(GetLastError());
+  _dosmaperr(GetLastError());
   return -1;
 }
 
@@ -530,7 +530,7 @@ int CDECL _wchmod(const wchar_t *path, int flags)
     if (newFlags == oldFlags || SetFileAttributesW(path, newFlags))
       return 0;
   }
-  __set_errno(GetLastError());
+  _dosmaperr(GetLastError());
   return -1;
 }
 
@@ -543,7 +543,7 @@ int CDECL _unlink(const char *path)
   if(DeleteFileA(path))
     return 0;
   TRACE("failed (%d)\n",GetLastError());
-  __set_errno(GetLastError());
+  _dosmaperr(GetLastError());
   return -1;
 }
 
@@ -556,7 +556,7 @@ int CDECL _wunlink(const wchar_t *path)
   if(DeleteFileW(path))
     return 0;
   TRACE("failed (%d)\n",GetLastError());
-  __set_errno(GetLastError());
+  _dosmaperr(GetLastError());
   return -1;
 }
 
@@ -621,7 +621,7 @@ int CDECL _close(int fd)
   else if (!CloseHandle(hand))
   {
     WARN(":failed-last error (%d)\n",GetLastError());
-    __set_errno(GetLastError());
+    _dosmaperr(GetLastError());
     ret = -1;
   }
   else
@@ -655,7 +655,7 @@ int CDECL _commit(int fd)
       return 0;
     }
     TRACE(":failed-last error (%d)\n",GetLastError());
-    __set_errno(GetLastError());
+    _dosmaperr(GetLastError());
     return -1;
   }
   TRACE(":ok\n");
@@ -701,7 +701,7 @@ int CDECL _dup2(int od, int nd)
     else
     {
       ret = -1;
-      __set_errno(GetLastError());
+      _dosmaperr(GetLastError());
     }
   }
   else
@@ -827,7 +827,7 @@ __int64 CDECL _lseeki64(int fd, __int64 offset, int whence)
     return ret.QuadPart;
   }
   TRACE(":error-last error (%d)\n",GetLastError());
-  __set_errno(GetLastError());
+  _dosmaperr(GetLastError());
   return -1;
 }
 
@@ -941,7 +941,7 @@ int CDECL _chsize(int fd, long size)
             if (pos >= 0)
             {
                 ret = SetEndOfFile(handle);
-                if (!ret) __set_errno(GetLastError());
+                if (!ret) _dosmaperr(GetLastError());
             }
 
             /* restore the file pointer */
@@ -1151,7 +1151,7 @@ int CDECL _futime(int fd, struct _utimbuf *t)
 
   if (!SetFileTime(hand, NULL, &at, &wt))
   {
-    __set_errno(GetLastError());
+    _dosmaperr(GetLastError());
     return -1 ;
   }
   return 0;
@@ -1324,7 +1324,7 @@ int CDECL _pipe(int *pfds, unsigned int psize, int textmode)
     UNLOCK_FILES();
   }
   else
-    __set_errno(GetLastError());
+    _dosmaperr(GetLastError());
 
   return ret;
 }
@@ -1415,7 +1415,7 @@ int CDECL _sopen( const char *path, int oflags, int shflags, ... )
 
   if (hand == INVALID_HANDLE_VALUE)  {
     WARN(":failed-last error (%d)\n",GetLastError());
-    __set_errno(GetLastError());
+    _dosmaperr(GetLastError());
     return -1;
   }
 
@@ -1445,7 +1445,7 @@ int CDECL _wsopen( const wchar_t* path, int oflags, int shflags, ... )
     free(patha);
     return retval;
   }
-  __set_errno(GetLastError());
+  _dosmaperr(GetLastError());
   free(patha);
   return -1;
 }
@@ -1490,7 +1490,7 @@ int CDECL _wopen(const wchar_t *path,int flags,...)
     return retval;
   }
 
-  __set_errno(GetLastError());
+  _dosmaperr(GetLastError());
   return -1;
 }
 
@@ -2237,7 +2237,7 @@ FILE * CDECL _wfsopen(const wchar_t *path, const wchar_t *mode, int share)
   }
   free(patha);
   free(modea);
-  __set_errno(GetLastError());
+  _dosmaperr(GetLastError());
   return NULL;
 }
 
@@ -2419,7 +2419,7 @@ FILE* CDECL freopen(const char *path, const char *mode,FILE* file)
       {
           file->_flag = 0;
           WARN(":failed-last error (%d)\n",GetLastError());
-          __set_errno(GetLastError());
+          _dosmaperr(GetLastError());
           file = NULL;
       }
     }
@@ -2634,7 +2634,7 @@ int CDECL remove(const char *path)
   if (DeleteFileA(path))
     return 0;
   TRACE(":failed (%d)\n",GetLastError());
-  __set_errno(GetLastError());
+  _dosmaperr(GetLastError());
   return -1;
 }
 
@@ -2647,7 +2647,7 @@ int CDECL _wremove(const wchar_t *path)
   if (DeleteFileW(path))
     return 0;
   TRACE(":failed (%d)\n",GetLastError());
-  __set_errno(GetLastError());
+  _dosmaperr(GetLastError());
   return -1;
 }
 
@@ -2660,7 +2660,7 @@ int CDECL rename(const char *oldpath,const char *newpath)
   if (MoveFileExA(oldpath, newpath, MOVEFILE_COPY_ALLOWED))
     return 0;
   TRACE(":failed (%d)\n",GetLastError());
-  __set_errno(GetLastError());
+  _dosmaperr(GetLastError());
   return -1;
 }
 
@@ -2673,7 +2673,7 @@ int CDECL _wrename(const wchar_t *oldpath,const wchar_t *newpath)
   if (MoveFileExW(oldpath, newpath, MOVEFILE_COPY_ALLOWED))
     return 0;
   TRACE(":failed (%d)\n",GetLastError());
-  __set_errno(GetLastError());
+  _dosmaperr(GetLastError());
   return -1;
 }
 
diff --git a/reactos/lib/sdk/crt/stdio/stat64.c b/reactos/lib/sdk/crt/stdio/stat64.c
index c8e450e2b63..533d05f5b90 100644
--- a/reactos/lib/sdk/crt/stdio/stat64.c
+++ b/reactos/lib/sdk/crt/stdio/stat64.c
@@ -34,7 +34,7 @@ int CDECL _tstat64(const _TCHAR *path, struct __stat64 *buf)
   if (!GetFileAttributesEx(path, GetFileExInfoStandard, &hfi))
   {
       TRACE("failed (%d)\n",GetLastError());
-      __set_errno(ERROR_FILE_NOT_FOUND);
+      _dosmaperr(ERROR_FILE_NOT_FOUND);
       return -1;
   }
 
@@ -101,7 +101,7 @@ int CDECL _fstat64(int fd, struct __stat64* buf)
   if (!buf)
   {
     WARN(":failed-NULL buf\n");
-    __set_errno(ERROR_INVALID_PARAMETER);
+    _dosmaperr(ERROR_INVALID_PARAMETER);
     return -1;
   }
 
@@ -125,7 +125,7 @@ int CDECL _fstat64(int fd, struct __stat64* buf)
     if (!GetFileInformationByHandle(hand, &hfi))
     {
       WARN(":failed-last error (%d)\n",GetLastError());
-      __set_errno(ERROR_INVALID_PARAMETER);
+      _dosmaperr(ERROR_INVALID_PARAMETER);
       return -1;
     }
     buf->st_mode = _S_IFREG | _S_IREAD;