commit 312fc9f812932fddf159006784e61d4536751214
parent fe8256cd9784987c3055043a2aa7be4a8c0699c7
Author: Christian Grothoff <christian@grothoff.org>
Date: Thu, 12 May 2011 12:33:40 +0000
warn users about pitfall with 32-bit vs. 64-bit off_t
Diffstat:
1 file changed, 22 insertions(+), 0 deletions(-)
diff --git a/doc/microhttpd.texi b/doc/microhttpd.texi
@@ -1403,6 +1403,28 @@ Return @mynull{} on error (i.e. invalid arguments, out of memory).
@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
+@verbatim
+#define _FILE_OFFSET_BITS 64
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <microhttpd.h>
+@end 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
+@code{off_t} (in which case the above would be wrong...).
@table @var
@item size
