From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 94CF0A0093; Fri, 10 Dec 2021 15:53:39 +0100 (CET) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 24BA54014F; Fri, 10 Dec 2021 15:53:39 +0100 (CET) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by mails.dpdk.org (Postfix) with ESMTP id 51A2740041 for ; Fri, 10 Dec 2021 15:53:38 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1639148018; x=1670684018; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=FlcE3ti5931VhBP9WDz9ydBg4DkWugpfZ1hbnPbzVVU=; b=Vop7m4yVh349bto5D4mTRHM/GLMLBNClEHrDBZj2c6LL0m+DN0DK+lWH XzELHNylrziXwdXNTGZTOVLrhHdhUJMJd13ow9WJRAadGepbiHptO5tb3 Nn7GokJqZG9luDPt6mwweYfCBG69ktY/fg4PRO2IItD1IXEJlCJf81aJc F2u5J1lfKLUxHG2XYdJvV3ydFvd0pAfHT47DHKyl6IKmmst00f5luPPXC KlinDa8RJgN5HI4ZsbfEwwLty+4k9NJxGDjO7yJXOP6lixJhFogk0/n93 yFaAAozI/7xTx+ZcL1Go9Wis/RmUbjyyYOympS4xOy90j0NuIiEpoIHPF Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10193"; a="237092418" X-IronPort-AV: E=Sophos;i="5.88,195,1635231600"; d="scan'208";a="237092418" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Dec 2021 06:53:37 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.88,195,1635231600"; d="scan'208";a="517299285" Received: from silpixa00399126.ir.intel.com ([10.237.223.86]) by fmsmga007.fm.intel.com with ESMTP; 10 Dec 2021 06:53:36 -0800 From: Bruce Richardson To: dev@dpdk.org Cc: dmitry.kozliuk@gmail.com, aconole@redhat.com, Bruce Richardson Subject: [PATCH] build/eal: add OS defines for C conditional checks Date: Fri, 10 Dec 2021 14:53:30 +0000 Message-Id: <20211210145330.108256-1-bruce.richardson@intel.com> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Define a set of macros in the build configuration to allow C runtime code to check the current OS environment. This saves the user having to use ifdefs for e.g. disabling particular tests on Windows. See included documentation changes for usage examples. Signed-off-by: Bruce Richardson --- doc/guides/contributing/coding_style.rst | 42 ++++++++++++++++++++++-- lib/eal/meson.build | 7 ++++ 2 files changed, 47 insertions(+), 2 deletions(-) diff --git a/doc/guides/contributing/coding_style.rst b/doc/guides/contributing/coding_style.rst index 0ec37c019b..e52ecb2b60 100644 --- a/doc/guides/contributing/coding_style.rst +++ b/doc/guides/contributing/coding_style.rst @@ -136,6 +136,12 @@ For example: Conditional Compilation ~~~~~~~~~~~~~~~~~~~~~~~ +.. note:: + + Conditional compilation should be used only when absolutely necessary, as it increases the number of target binaries that need to be built and tested. + See below for details of some utility macros/defines available to allow ifdefs/macros to be replaced by C conditional in some cases. + + * When code is conditionally compiled using ``#ifdef`` or ``#if``, a comment may be added following the matching ``#endif`` or ``#else`` to permit the reader to easily discern where conditionally compiled code regions end. * This comment should be used only for (subjectively) long regions, regions greater than 20 lines, or where a series of nested ``#ifdef``'s may be confusing to the reader. @@ -165,9 +171,41 @@ Conditional Compilation /* Or here. */ #endif /* !COMPAT_43 */ -.. note:: +Defines to Avoid Conditional Compilation +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +In many cases in DPDK, one wants to optionally compile code based on the target platform, +or runtime environment. +While this can be done using the conditional compilation directives, +e.g. ``#ifdef RTE_EXEC_ENV_LINUX``, present in DPDK for many releases, +this can also be done in many cases using regular ``if`` statements and the following defines: + +* ``RTE_ENV_FREEBSD``, ``RTE_ENV_LINUX``, ``RTE_ENV_WINDOWS`` - these define ids for each operating system environment. +* ``RTE_EXEC_ENV`` - this defines the id of the current environment, i.e. one of the items in list above. +* ``RTE_EXEC_ENV_IS_FREEBSD``, ``RTE_EXEC_ENV_IS_LINUX``, ``RTE_EXEC_ENV_IS_WINDOWS`` - 0/1 values indicating if the current environment is that specified, + shortcuts for checking e.g. ``RTE_EXEC_ENV == RTE_ENV_WINDOWS`` + +Examples of use: + +.. code-block:: c + + /* report a unit tests as unsupported on Windows */ + if (RTE_EXEC_ENV_IS_WINDOWS) + return TEST_SKIPPED; + + /* set different default values depending on OS Environment */ + switch (RTE_EXEC_ENV) { + case RTE_ENV_FREEBSD: + default = x; + break; + case RTE_ENV_LINUX: + default = y; + break; + case RTE_ENV_WINDOWS: + default = z; + break; + } - Conditional compilation should be used only when absolutely necessary, as it increases the number of target binaries that need to be built and tested. C Types ------- diff --git a/lib/eal/meson.build b/lib/eal/meson.build index 1722924f67..056beb9461 100644 --- a/lib/eal/meson.build +++ b/lib/eal/meson.build @@ -10,6 +10,13 @@ if not is_windows subdir('unix') endif +exec_envs = {'freebsd': 0, 'linux': 1, 'windows': 2} +foreach env, id:exec_envs + dpdk_conf.set('RTE_ENV_' + env.to_upper(), id) + dpdk_conf.set10('RTE_EXEC_ENV_IS_' + env.to_upper(), (exec_env == env)) +endforeach +dpdk_conf.set('RTE_EXEC_ENV', exec_envs[exec_env]) + dpdk_conf.set('RTE_EXEC_ENV_' + exec_env.to_upper(), 1) subdir(exec_env) -- 2.32.0