Using C, how do we find the max size of char* allowed by a file system?
+1
A:
My assumption here is that you are asking for "What is the maximum allowable length of a file name allowed by a file system?"
This is dependent on the OS and how the filesystem is implemented, but most systems have defined macros that can be referenced.
In Linux, limits.h, the value can be reference by the macro PATH_MAX, 4096 (Current as of kernel 2.6.35)
In Windows, WinDef.h, the value can be reference by the macro MAX_PATH, 260 (Current as of Windows 7). This does not include the use of UNC paths (See comment below).
linuxuser27
2010-09-16 00:46:24
In Windows, the story is much more complex as UNC paths have a separate (and much larger) maximum length. The type file system to which the path points matters too. See http://msdn.microsoft.com/en-us/library/aa365247%28VS.85%29.aspx for a bunch of gory details.
RBerteig
2010-09-16 00:55:22
+1 Good point. Updated solution to mention.
linuxuser27
2010-09-16 01:04:44
I think a completely portable solution that uses only the C library would have to rely on FILENAME_MAX (from `stdio.h`).
Dan Moulding
2010-09-16 01:48:31