Nowadays, argument LEN of to_xfer_partial can be zero in some cases,
and each implementation may do nothing and return zero, indicating
transfer is done. That is fine. However, when we change
to_xfer_partial to return target_xfer_status, we have to check every
return value of most of to_xfer_partial implementations, return
TARGET_XFER_DONE if return value is zero.
This patch simplifies this by checking LEN in target_xfer_partial, and
return 0 if LEN is zero. Regression tested on x86_84-linux. Is it
OK?
gdb:
2014-02-07 Yao Qi <yao@codesourcery.com>
* target.c (target_xfer_partial): Return zero if LEN is zero.
2014-02-07 Yao Qi <yao@codesourcery.com>
+ * target.c (target_xfer_partial): Return zero if LEN is zero.
+
+2014-02-07 Yao Qi <yao@codesourcery.com>
+
* auxv.c (procfs_xfer_auxv): Replace -1 with TARGET_XFER_E_IO.
(ld_so_xfer_auxv): Likewise.
* bfd-target.c (target_bfd_xfer_partial): Likewise.
gdb_assert (ops->to_xfer_partial != NULL);
+ /* Transfer is done when LEN is zero. */
+ if (len == 0)
+ return 0;
+
if (writebuf && !may_write_memory)
error (_("Writing to memory is not allowed (addr %s, len %s)"),
core_addr_to_string_nz (offset), plongest (len));