From ea1cc83b50dc44df1f38891d9c95e99e2f127a80 Mon Sep 17 00:00:00 2001 From: Andreas Schuh Date: Tue, 1 Mar 2016 22:00:58 +0000 Subject: [PATCH] doc: Use of find_package COMPONENTS or inclusion as subproject --- index.html | 41 +++++++++++++++++++++++++---------------- 1 file changed, 25 insertions(+), 16 deletions(-) diff --git a/index.html b/index.html index 5b13c58..d3aee33 100644 --- a/index.html +++ b/index.html @@ -39,7 +39,7 @@
Table of contents
Introduction
Download and Installation
-
Finding and Linking to gflags using CMake
+
Linking to gflags using CMake
DEFINE: Defining Flags In Program
Accessing the Flag
DECLARE: Using the Flag in a Different File
@@ -103,28 +103,37 @@ You can clone the project using the command:

Build and installation instructions are provided in the INSTALL file.

-

Finding and Linking to gflags using CMake

+

Linking to gflags using CMake

-

Using gflags within a project which uses CMake for its build system is easy. Therefore, simply add the following CMake code to your CMakeLists.txt file. +

Using gflags within a project which uses CMake for its build system is easy. +You can either require an external installation of the gflags package and find it using CMake's find_package +command, or include the gflags project as subtree or submodule within your project's source tree and add the directory +using CMake's add_subdirectory command. + +

To use an external gflags installation, add the following CMake code to your CMakeLists.txt file.

-

The following CMake variables can be set to request a particular imported gflags library target -to link against. By default, the multi-threaded gflags library with static linkage is chosen if available. -It is recommended to only define these variables if a specific library must be used. -Otherwise, the gflags-config.cmake module will choose a suitable and available library for you. -These configuration options can also be added to the CMake cache (using CMake's option command) so they can -be modified via the CMake GUI or specified as arguments to CMake instead, e.g., -"cmake -D gflags_SHARED:BOOL=TRUE -D gflags_NOTHREADS:BOOL=FALSE <foo_source_dir>".

-
-   set(gflags_SHARED    FALSE)
-   set(gflags_NOTHREADS FALSE)
-
- -

Find gflags installation. The gflags_DIR variable must be set to the <prefix>/lib/cmake/gflags directory +

Find gflags installation. The gflags_DIR variable must be set to the <prefix>/lib/cmake/gflags directory containing the gflags-config.cmake file if <prefix> is a non-standard location. Otherwise, CMake should find the gflags installation automatically.

    find_package(gflags REQUIRED)
+

To request a particular imported gflags library target to link against, use the COMPONENTS option of +the find_package command. For example, to force the use of the single-threaded static library, use the command

+
+   find_package(gflags COMPONENTS nothreads_static)
+
+

Note that this will raise a fatal error when the installed gflags package does not contain the requested library. +It is therefore recommended to only specify the particular component to look for if a specific library must be used. +Otherwise, the gflags-config.cmake module will choose a suitable and available library for you. By default, the +multi-threaded gflags library with shared linkage is chosen if available.

+ +

When the source tree of the gflags project is included as subtree or submodule in the "gflags" directory of your project, +replace the above find_package command by add_subdirectory(gflags). See the top of the gflags/CMakeLists.txt +file for a listing of available CMake variables that can be set before this command to configure the build of the +gflags library. The default build settings are the build of a single-threaded static library which does not require +any installation of the gflags subproject products.

+

Finally, add your executable build target which uses gflags to parse the command arguments with dependency on the imported gflags library target: