diff mbox series

[v9,02/30] eal/include: add new packing macros

Message ID 1736383715-31703-3-git-send-email-andremue@linux.microsoft.com (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers
Series fix packing of structs when building with MSVC |

Checks

Context Check Description
ci/checkpatch success coding style OK

Commit Message

Andre Muezerie Jan. 9, 2025, 12:48 a.m. UTC 
MSVC struct packing is not compatible with GCC. Add macro
__rte_packed_begin which can be used to push existing pack value
and set packing to 1-byte. Add macro __rte_packed_end to restore
the pack value prior to the push.

Macro __rte_packed_end is deliberately utilized to trigger a
MSVC compiler warning if no existing packing has been pushed allowing
easy identification of locations where the __rte_packed_begin is
missing.

Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
Acked-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
---
 lib/eal/include/rte_common.h | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/lib/eal/include/rte_common.h b/lib/eal/include/rte_common.h
index 4d299f2b36..d72f8590bd 100644
--- a/lib/eal/include/rte_common.h
+++ b/lib/eal/include/rte_common.h
@@ -101,11 +101,17 @@  typedef uint16_t unaligned_uint16_t;
 
 /**
  * Force a structure to be packed
+ * Usage:
+ *     struct __rte_packed_begin mystruct { ... } __rte_packed_end;
+ *     union __rte_packed_begin myunion { ... } __rte_packed_end;
+ * Note: alignment attributes when present should precede __rte_packed_begin.
  */
 #ifdef RTE_TOOLCHAIN_MSVC
-#define __rte_packed
+#define __rte_packed_begin __pragma(pack(push, 1))
+#define __rte_packed_end __pragma(pack(pop))
 #else
-#define __rte_packed __attribute__((__packed__))
+#define __rte_packed_begin
+#define __rte_packed_end __attribute__((__packed__))
 #endif
 
 /**