#include <sys/cygwin.h>

ssize_t cygwin_conv_path(cygwin_conv_path_t what, const void * from, void * to, size_t size);


Use this function to convert POSIX paths in from to Win32 paths in to or, vice versa, Win32 paths in from to POSIX paths in to. what defines the direction of this conversion and can be any of the below values.

  CCP_POSIX_TO_WIN_A      /* from is char *posix, to is char *win32       */
  CCP_POSIX_TO_WIN_W,     /* from is char *posix, to is wchar_t *win32    */
  CCP_WIN_A_TO_POSIX,     /* from is char *win32, to is char *posix       */
  CCP_WIN_W_TO_POSIX,     /* from is wchar_t *win32, to is char *posix    */

You can additionally or the following values to what, to define whether you want the resulting path in to to be absolute or if you want to keep relative paths in relative notation. Creating absolute paths is the default.

  CCP_ABSOLUTE = 0,         /* Request absolute path (default).             */
  CCP_RELATIVE = 0x100      /* Request to keep path relative.               */
  CCP_PROC_CYGDRIVE = 0x200 /* Request to return /proc/cygdrive path
                               (only with CCP_*_TO_POSIX).                  */

size is the size of the buffer pointed to by to in bytes. If size is 0, cygwin_conv_path just returns the required buffer size in bytes. Otherwise, it returns 0 on success, or -1 on error and errno is set to one of the below values.

    EINVAL        what has an invalid value or from is NULL.
    EFAULT        from or to point into nirvana.
    ENAMETOOLONG  the resulting path is longer than 32K, or, in case
                  of what == CCP_POSIX_TO_WIN_A, longer than MAX_PATH.
    ENOSPC        size is less than required for the conversion.


Example 2.1. Example use of cygwin_conv_path

#include <sys/cygwin.h>

/* Conversion from incoming Win32 path given as wchar_t *win32 to POSIX path.
   If incoming path is a relative path, stick to it.  First ask how big
   the output buffer has to be and allocate space dynamically. */
ssize_t size;
char *posix;
size = cygwin_conv_path (CCP_WIN_W_TO_POSIX | CCP_RELATIVE, win32, NULL, 0);
if (size < 0)
  perror ("cygwin_conv_path");
    posix = (char *) malloc (size);
    if (cygwin_conv_path (CCP_WIN_W_TO_POSIX | CCP_RELATIVE, win32,
                          posix, size))
      perror ("cygwin_conv_path");