libxlutil: avoid almost-undefined behavior

While only value computations of an object are disallowed in the
presence of another unsequenced side effect, at least gcc 4.3 looks to
extend this to taking the object's address. The resulting warning causes
the build to fail, because of -Werror.

While there also correct an adjacent comment.

Fixes: bdc0799fe26a ("libxlu: introduce xlu_pci_parse_spec_string()")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Ian Jackson <ian.jackson@eu.citrix.com>

diff --git a/tools/libs/util/libxlu_pci.c b/tools/libs/util/libxlu_pci.c
index ad88fee08853a7c17d3628177946f5f55afbc379..551d8e3aedc290e893f815baf4498cb29d000320 100644 (file)
--- a/tools/libs/util/libxlu_pci.c
+++ b/tools/libs/util/libxlu_pci.c
@@ -155,9 +155,10 @@ int xlu_pci_parse_spec_string(XLU_Config *cfg, libxl_device_pci *pci,
     if (!ret) {
         bdf_present = true;
 
-        /* Check whether 'vslot' if present */
+        /* Check whether 'vslot' is present */
         if (*ptr == '@') {
-            ret = parse_vslot(&pci->vdevfn, ++ptr, &ptr);
+            ++ptr;
+            ret = parse_vslot(&pci->vdevfn, ptr, &ptr);
             if (ret)
                 return ret;
         }