+
−@node mmap
+
−@section @code{mmap}
+
−@findex mmap
+
−
+
−POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/mmap.html}
+
−
+
−Gnulib module: ---
+
−
+
−Portability problems fixed by Gnulib:
+
−@itemize
+
−@end itemize
+
−
+
−Portability problems not fixed by Gnulib:
+
−@itemize
+
−@item
+
−This function is missing on some platforms:
+
−mingw, MSVC 9, BeOS.
+
−@item
+
−On platforms where @code{off_t} is a 32-bit type, this function may not
+
−work correctly across the entire data range of files larger than 2 GB.
+
−The fix is to use the @code{AC_SYS_LARGEFILE} macro.
+
−@item
+
−To get anonymous memory, on some platforms, you can use the flags
+
−@code{MAP_ANONYMOUS | MAP_PRIVATE} and @code{-1} instead of a file descriptor;
+
−on others you have to use a read-only file descriptor of @file{/dev/zero}.
+
−@item
+
−On HP-UX, passing a non-NULL first argument, as a hint for the address (even
+
−without @code{MAP_FIXED}, often causes @code{mmap} to fail.  Better pass NULL
+
−in this case.
+
−@item
+
−On HP-UX, @code{MAP_FIXED} basically never works.  On other platforms, it depends
+
−on the circumstances whether memory can be returned at a given address.
+
−@end itemize