[GNUnet-SVN] r15212 - libmicrohttpd/doc

[gnunet]

Author: grothoff
Date: 2011-05-12 14:33:40 +0200 (Thu, 12 May 2011)
New Revision: 15212

Modified:
   libmicrohttpd/doc/microhttpd.texi
Log:
warn users about pitfall with 32-bit vs. 64-bit off_t

Modified: libmicrohttpd/doc/microhttpd.texi
===================================================================
--- libmicrohttpd/doc/microhttpd.texi   2011-05-12 12:32:19 UTC (rev 15211)
+++ libmicrohttpd/doc/microhttpd.texi   2011-05-12 12:33:40 UTC (rev 15212)
@@ -1403,7 +1403,29 @@
 @deftypefun {struct MHD_Response *} MHD_create_response_from_fd_at_offset 
(uint64_t size, int fd, off_t offset)
 Create a response object.  The response object can be extended with
 header information and then it can be used any number of times.
+Note that you need to be a bit careful about @code{off_t} when
+writing this code.  Depending on your platform, @mhd{} is likely
+to have been compiled with support for 64-bit files.  When you
+compile your own application, you must make sure that @code{off_t}
+is also a 64-bit value.  If not, your compiler may pass a 32-bit
+value as @code{off_t}, which will result in 32-bits of garbage.
 
+If you use the autotools, use the @code{AC_SYS_LARGEFILE} autoconf
+macro and make sure to include the generated @file{config.h} file
+before @file{microhttpd.h} to avoid problems.  If you do not have a
+build system and only want to run on a GNU/Linux system, you could
+also use
address@hidden
+#define _FILE_OFFSET_BITS 64
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <microhttpd.h>
address@hidden verbatim
+to ensure 64-bit @code{off_t}.  Note that if your operating system
+does not support 64-bit files, @mhd{} will be compiled with a 32-bit
address@hidden (in which case the above would be wrong...).
+
 @table @var
 @item size
 size of the data portion of the response (number of bytes to transmit from the