https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=5c759ab2f45f966b5458d49a1a0e23c15d5c1eca
commit 5c759ab2f45f966b5458d49a1a0e23c15d5c1eca Author: Corinna Vinschen <cori...@vinschen.de> Date: Tue May 31 16:33:21 2016 +0200 realpath: Handle Win32 and NT long path prefixes So far drive letter paths have been handled special since path_conv leaves the incoming path untouched except for converting backslashes to forward slashes. However, if the incoming path starts with a long path prefix, the same problem occurs. Therefore handle all paths starting with a backslahs the same way. Signed-off-by: Corinna Vinschen <cori...@vinschen.de> Diff: --- winsup/cygwin/path.cc | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc index 250871d..18d5c1d 100644 --- a/winsup/cygwin/path.cc +++ b/winsup/cygwin/path.cc @@ -3560,10 +3560,12 @@ realpath (const char *__restrict path, char *__restrict resolved) potentially invalid resolved. */ __try { - /* Win32 drive letter paths have to be converted to a POSIX path first, - because path_conv leaves the incoming path untouched except for - converting backslashes to forward slashes. */ - if (isdrive (path)) + /* Win32 drive letter paths and, generally, any path starting with a + backslash, have to be converted to a POSIX path first, because + path_conv leaves the incoming path untouched except for converting + backslashes to forward slashes. This also covers '\\?\ and '\??\' + path prefixes. */ + if (isdrive (path) || path[0] == '\\') { tpath = tp.c_get (); mount_table->conv_to_posix_path (path, tpath, 0);