build: use C11 standard

As previously announced, DPDK 23.11 will require a C11 supporting
compiler and will use the C11 standard in all builds.

Forcing use of the C standard, rather than the standard with
GNU extensions, means that some posix definitions which are not in
the C standard are unavailable by default. We fix this by ensuring
the correct defines or cflags are passed to the components that
need them.

Signed-off-by: Bruce Richardson <[email protected]>
Acked-by: Morten Brørup <[email protected]>
Acked-by: Tyler Retzlaff <[email protected]>
Tested-by: Ali Alnubani <[email protected]>

Author: bruce-richardson

doc/guides/linux_gsg/sys_reqs.rst

@@ -27,7 +27,8 @@ Compilation of the DPDK
     The setup commands and installed packages needed on various systems may be different.
     For details on Linux distributions and the versions tested, please consult the DPDK Release Notes.
 
-*   General development tools including a supported C compiler such as gcc (version 4.9+) or clang (version 3.4+),
+*   General development tools including a C compiler supporting the C11 standard,
+    including standard atomics, for example: GCC (version 5.0+) or Clang (version 3.6+),
     and ``pkg-config`` or ``pkgconf`` to be used when building end-user binaries against DPDK.
 
     * For RHEL/Fedora systems these can be installed using ``dnf groupinstall "Development Tools"``

doc/guides/rel_notes/deprecation.rst

@@ -17,24 +17,6 @@ Other API and ABI deprecation notices are to be posted below.
 Deprecation Notices
 -------------------
 
-* C Compiler: From DPDK 23.11 onwards,
-  building DPDK will require a C compiler which supports the C11 standard,
-  including support for C11 standard atomics.
-
-  More specifically, the requirements will be:
-
-  * Support for flag "-std=c11" (or similar)
-  * __STDC_NO_ATOMICS__ is *not defined* when using c11 flag
-
-  Please note:
-
-  * C11, including standard atomics, is supported from GCC version 5 onwards,
-    and is the default language version in that release
-    (Ref: https://gcc.gnu.org/gcc-5/changes.html)
-  * C11 is the default compilation mode in Clang from version 3.6,
-    which also added support for standard atomics
-    (Ref: https://releases.llvm.org/3.6.0/tools/clang/docs/ReleaseNotes.html)
-
 * build: Enabling deprecated libraries (``flow_classify``, ``kni``)
   won't be possible anymore through the use of the ``disable_libs`` build option.
   A new build option for deprecated libraries will be introduced instead.

doc/guides/rel_notes/release_23_11.rst

@@ -20,6 +20,23 @@ DPDK Release 23.11
       ninja -C build doc
       xdg-open build/doc/guides/html/rel_notes/release_23_11.html
 
+* Build Requirements: From DPDK 23.11 onwards,
+  building DPDK will require a C compiler which supports the C11 standard,
+  including support for C11 standard atomics.
+
+  More specifically, the requirements will be:
+
+  * Support for flag "-std=c11" (or similar)
+  * __STDC_NO_ATOMICS__ is *not defined* when using c11 flag
+
+  Please note:
+
+  * C11, including standard atomics, is supported from GCC version 5 onwards,
+    and is the default language version in that release
+    (Ref: https://gcc.gnu.org/gcc-5/changes.html)
+  * C11 is the default compilation mode in Clang from version 3.6,
+    which also added support for standard atomics
+    (Ref: https://releases.llvm.org/3.6.0/tools/clang/docs/ReleaseNotes.html)
 
 New Features
 ------------

drivers/common/mlx5/linux/meson.build

@@ -231,11 +231,12 @@ if  libmtcr_ul_found
 endif
 
 foreach arg:has_sym_args
-    mlx5_config.set(arg[0], cc.has_header_symbol(arg[1], arg[2], dependencies: libs))
+    mlx5_config.set(arg[0], cc.has_header_symbol(arg[1], arg[2], dependencies: libs, args: cflags))
 endforeach
 foreach arg:has_member_args
     file_prefix = '#include <' + arg[1] + '>'
-    mlx5_config.set(arg[0], cc.has_member(arg[2], arg[3], prefix : file_prefix, dependencies: libs))
+    mlx5_config.set(arg[0],
+            cc.has_member(arg[2], arg[3], prefix : file_prefix, dependencies: libs, args: cflags))
 endforeach
 
 # Build Glue Library

drivers/net/failsafe/meson.build

@@ -7,7 +7,6 @@ if is_windows
     subdir_done()
 endif
 
-cflags += '-std=gnu99'
 cflags += '-D_DEFAULT_SOURCE'
 cflags += '-D_XOPEN_SOURCE=700'
 cflags += '-pedantic'

drivers/net/mlx4/meson.build

@@ -103,12 +103,12 @@ has_sym_args = [
 config = configuration_data()
 foreach arg:has_sym_args
     config.set(arg[0], cc.has_header_symbol(arg[1], arg[2],
-        dependencies: libs))
+        dependencies: libs, args: cflags))
 endforeach
 foreach arg:has_member_args
     file_prefix = '#include <' + arg[1] + '>'
     config.set(arg[0], cc.has_member(arg[2], arg[3],
-        prefix: file_prefix, dependencies: libs))
+        prefix: file_prefix, dependencies: libs, args: cflags))
 endforeach
 configure_file(output : 'mlx4_autoconf.h', configuration : config)
 

lib/acl/acl_run_altivec.h

@@ -41,7 +41,7 @@ resolve_priority_altivec(uint64_t transition, int n,
 {
 	uint32_t x;
 	xmm_t results, priority, results1, priority1;
-	__vector bool int selector;
+	__vector __bool int selector;
 	xmm_t *saved_results, *saved_priority;
 
 	for (x = 0; x < categories; x += RTE_ACL_RESULTS_MULTIPLIER) {
@@ -110,7 +110,7 @@ transition4(xmm_t next_input, const uint64_t *trans,
 	xmm_t in, node_type, r, t;
 	xmm_t dfa_ofs, quad_ofs;
 	xmm_t *index_mask, *tp;
-	__vector bool int dfa_msk;
+	__vector __bool int dfa_msk;
 	__vector signed char zeroes = {};
 	union {
 		uint64_t d64[2];

lib/eal/common/eal_common_errno.c

@@ -4,6 +4,7 @@
 
 /* Use XSI-compliant portable version of strerror_r() */
 #undef _GNU_SOURCE
+#define _POSIX_C_SOURCE 200809L
 
 #include <stdio.h>
 #include <string.h>

meson.build

@@ -9,6 +9,7 @@ project('DPDK', 'c',
         license: 'BSD',
         default_options: [
             'buildtype=release',
+            'c_std=c11',
             'default_library=static',
             'warning_level=2',
         ],