Cmake Call External Program

OverviewAn ESP-IDF project can be seen as an amalgamation of a number of components.For example, for a webserver that shows the current humidity, there could be:. The ESP32 base libraries (libc, ROM bindings, etc). The WiFi drivers.

A TCP/IP stack. The FreeRTOS operating system. A webserver.

A driver for the humidity sensor. Main code tying it all togetherESP-IDF makes these components explicit and configurable. To do that,when a project is compiled, the build system will look up all thecomponents in the ESP-IDF directories, the project directories and(optionally) in additional custom component directories. It thenallows the user to configure the ESP-IDF project using a a text-basedmenu system to customize each component. After the components in theproject are configured, the build system will compile the project. Concepts. A “project” is a directory that contains all the files and configuration to build a single “app” (executable), as well as additional supporting elements such as a partition table, data/filesystem partitions, and a bootloader.

“Project configuration” is held in a single file called sdkconfig in the root directory of the project. This configuration file is modified via idf.py menuconfig to customise the configuration of the project. A single project contains exactly one project configuration. An “app” is an executable which is built by ESP-IDF. A single project will usually build two apps - a “project app” (the main executable, ie your custom firmware) and a “bootloader app” (the initial bootloader program which launches the project app). “components” are modular pieces of standalone code which are compiled into static libraries (.a files) and linked into an app. Some are provided by ESP-IDF itself, others may be sourced from other places.

“Target” is the hardware for which an application is built. At the moment, ESP-IDF supports only one target, esp32.Some things are not part of the project:. “ESP-IDF” is not part of the project. Instead it is standalone, and linked to the project via the IDFPATH environment variable which holds the path of the esp-idf directory. This allows the IDF framework to be decoupled from your project. The toolchain for compilation is not part of the project. The toolchain should be installed in the system command line PATH.

Idf.pyThe idf.py command line tool provides a front-end for easily managing your project builds. It manages the following tools:., which configures the project to be built.

A command line build tool (either build or GNU Make). for flashing ESP32.The contains a brief introduction to how to set up idf.py to configure, build, and flash projects.idf.py should be run in an ESP-IDF “project” directory, ie one containing a CMakeLists.txt file. Older style projects with a Makefile will not work with idf.py.Type idf.py -help for a full list of commands. Here are a summary of the most useful ones:.idf.py menuconfig runs the “menuconfig” tool to configure the project.idf.py build will build the project found in the current directory. This can involve multiple steps:. Create the build directory if needed. The sub-directory build is used to hold build output, although this can be changed with the -B option.

Run as necessary to configure the project and generate build files for the main build tool. Run the main build tool ( or GNU Make).

By default, the build tool is automatically detected but it can be explicitly set by passing the -G option to idf.py.Building is incremental so if no source files or configuration has changed since the last build, nothing will be done.idf.py clean will “clean” the project by deleting build output files from the build directory, forcing a “full rebuild” the next time the project is built. Cleaning doesn’t delete CMake configuration output and some other files.idf.py fullclean will delete the entire “build” directory contents. This includes all CMake configuration output. The next time the project is built, CMake will configure it from scratch.

Note that this option recursively deletes all files in the build directory, so use with care. Project configuration is not deleted.idf.py flash will automatically build the project if necessary, and then flash it to an ESP32. The -p and -b options can be used to set serial port name and flasher baud rate, respectively.idf.py monitor will display serial output from the ESP32. The -p option can be used to set the serial port name. Type Ctrl- to exit the monitor.

See for more details about using the monitor.Multiple idf.py commands can be combined into one. For example, idf.py -p COM4 clean flash monitor will clean the source tree, then build the project and flash it to the ESP32 before running the serial monitor.

Advanced Commands. idf.py app, idf.py bootloader, idf.py partitiontable can be used to build only the app, bootloader, or partition table from the project as applicable. There are matching commands idf.py app-flash, etc. To flash only that single part of the project to the ESP32.

idf.py -p PORT eraseflash will use esptool.py to erase the ESP32’s entire flash chip. idf.py size prints some size information about the app. Size-components and size-files are similar commands which print more detailed per-component or per-source-file information, respectively. If you define variable -DOUTPUTJSON=1 when running CMake (or idf.py), the output will be formatted as JSON not as human readable text. idf.py reconfigure re-runs even if it doesn’t seem to need re-running.

This isn’t necessary during normal usage, but can be useful after adding/removing files from the source tree, or when modifying CMake cache variables. For example, idf.py -DNAME='VALUE' reconfigure can be used to set variable NAME in CMake cache to value VALUE.The order of multiple idf.py commands on the same invocation is not important, they will automatically be executed in the correct order for everything to take effect (ie building before flashing, erasing before flashing, etc.). Idf.py optionsTo list all available options, run idf.py -help.C allows overriding the project directory from the default current working directory.B allows overriding the build directory from the default build subdirectory of the project directory.ccache flag can be used to enable when compiling source files, if the tool is installed. This can dramatically reduce some build times.Note that some older versions of CCache may exhibit bugs on some platforms, so if files are not rebuilt as expected then try disabling ccache and build again.

CCache can be enabled by default by setting the IDFENABLECCACHE environment variable to a non-zero value.- -v flag causes both idf.py and the build system to produce verbose build output. This can be useful for debugging build problems. Mkdir -p buildcd buildcmake.G Ninja # or 'Unix Makefiles'ninjaIn the above list, the cmake command configures the project and generates build files for use with the final build tool. In this case the final build tool is: running ninja actually builds the project.It’s not necessary to run cmake more than once. After the first build, you only need to run ninja each time. Ninja will automatically re-invoke cmake if the project needs reconfiguration.If using CMake with ninja or make, there are also targets for more of the idf.py sub-commands - for example running make menuconfig or ninja menuconfig in the build directory will work the same as idf.py menuconfig.

Setting the Python InterpreterCurrently, ESP-IDF only works with Python 2.7. If you have a system where the default python interpreter is Python 3.x, this can lead to problems.If using idf.py, running idf.py as python2 $IDFPATH/tools/idf.py. Will work around this issue ( idf.py will tell other Python processes to use the same Python interpreter). You can set up a shell alias or another script to simplify the command.If using CMake directly, running cmake -D PYTHON=python2.

Will cause CMake to override the default Python interpreter.If using an IDE with CMake, setting the PYTHON value as a CMake cache override in the IDE UI will override the default Python interpreter.To manage the Python version more generally via the command line, check out the tools. These let you change the default python version. MyProject/- CMakeLists.txt- sdkconfig- components/ - component1/ - CMakeLists.txt- Kconfig- src1.c- component2/ - CMakeLists.txt- Kconfig- src1.c- include/ - component2.h- main/ - CMakeLists.txt- src1.c- src2.c- build/This example “myProject” contains the following elements:. A top-level project CMakeLists.txt file.

This is the primary file which CMake uses to learn how to build the project; and may set project-wide CMake variables. It includes the file whichimplements the rest of the build system. Finally, it sets the project name and defines the project. “sdkconfig” project configuration file. This file is created/updated when idf.py menuconfig runs, and holds configuration for all of the components in the project (including ESP-IDF itself).

The “sdkconfig” file may or may not be added to the source control system of the project. Optional “components” directory contains components that are part of the project. A project does not have to contain custom components of this kind, but it can be useful for structuring reusable code or including third party components that aren’t part of ESP-IDF. Alternatively, EXTRACOMPONENTDIRS can be set in the top-level CMakeLists.txt to look for components in other places. See the section for more info. If you have a lot of source files in your project, we recommend grouping most into components instead of putting them all in “main”. “main” directory is a special component that contains source code for the project itself.

“main” is a default name, the CMake variable COMPONENTDIRS includes this component but you can modify this variable. “build” directory is where build output is created. This directory is created by idf.py if it doesn’t already exist. CMake configures the project and generates interim build files in this directory. Then, after the main build process is run, this directory will also contain interim object files and libraries as well as final binary output files. This directory is usually not added to source control or distributed with the project source code.Component directories each contain a component CMakeLists.txt file. This file contains variable definitionsto control the build process of the component, and its integration into the overall project.

See for more details.Each component may also include a Kconfig file defining the options that can be set via menuconfig. Some components may also include Kconfig.projbuild and projectinclude.cmake files, which are special files for.

Optional Project VariablesThese variables all have default values that can be overridden for custom behaviour. Look in for all of the implementation details. COMPONENTDIRS, COMPONENTSDIRS: Directories to search for components. Defaults to IDFPATH/components, PROJECTDIR/components, and EXTRACOMPONENTDIRS. Override this variable if you don’t want to search for components in these places. EXTRACOMPONENTDIRS, EXTRACOMPONENTSDIRS: Optional list of additional directories to search for components.

Paths can be relative to the project directory, or absolute. COMPONENTS: A list of component names to build into the project. Defaults to all components found in the COMPONENTDIRS directories. Use this variable to “trim down” the project for faster build times. Note that any component which “requires” another component via the REQUIRES or PRIVREQUIRES arguments on component registration will automatically have it added to this list, so the COMPONENTS list can be very short.Any paths in these variables can be absolute paths, or set relative to the project directory.To set these variables, use the ie set(VARIABLE 'VALUE'). The set commands should be placed after the cmakeminimum(.) line but before the include(.) line. Renaming main componentThe build system provides special treatment to the main component.

It is a component that gets automatically added to the build providedthat it is in the expected location, PROJECTDIR/main. All other components in the build are also added as its dependencies,saving the user from hunting down dependencies and providing a build that works right out of the box. Renaming the main componentcauses the loss of these behind-the-scences heavy lifting, requiring the user to specify the location of the newly renamed componentand manually specifying its dependencies. Specifically, the steps to renaming main are as follows:. Rename main directory. Set EXTRACOMPONENTDIRS in the project CMakeLists.txt to include the renamed main directory. Specify the dependencies in the renamed component’s CMakeLists.txt file via REQUIRES or PRIVREQUIRES arguments.

Multiple components with the same nameWhen ESP-IDF is collecting all the components to compile, it will do this in the order specified by COMPONENTDIRS; by default, this means ESP-IDF’s internal components first, then the project’s components, and finally any components set in EXTRACOMPONENTDIRS. If two or more of these directoriescontain component sub-directories with the same name, the component in the last place searched is used. This allows, for example, overriding ESP-IDF componentswith a modified version by copying that component from the ESP-IDF components directory to the project components directory and then modifying it there.If used in this way, the ESP-IDF directory itself can remain untouched. Idfcomponentregister ( SRCS 'foo.c' 'bar.c' INCLUDEDIRS 'include' REQUIRES mbedtls ).

SRCS is a list of source files (.c,.cpp,.cc,.S). These source files will be compiled into the component library. INCLUDEDIRS is a list of directories to add to the global include search path for any component which requires this component, and also the main source files. REQUIRES is not actually required, but it is very often required to declare what other components this component will use. See.A library with the name of the component will be built and linked into the final app.Directories are usually specified relative to the CMakeLists.txt file itself, although they can be absolute.There are other arguments that can be passed to idfcomponentregister. These argumentsare discussed.See and for more complete component CMakeLists.txt examples. Preset Component VariablesThe following component-specific variables are available for use inside component CMakeLists, but should not be modified:.

COMPONENTDIR: The component directory. Evaluates to the absolute path of the directory containing CMakeLists.txt.

The component path cannot contain spaces. This is the same as the CMAKECURRENTSOURCEDIR variable. COMPONENTNAME: Name of the component. Same as the name of the component directory. COMPONENTALIAS: Alias of the library created internally by the build system for the component. COMPONENTLIB: Name of the library created internally by the build system for the component.The following variables are set at the project level, but available for use in component CMakeLists:.

CONFIG.: Each value in the project configuration has a corresponding variable available in cmake. All names begin with CONFIG.

ESPPLATFORM: Set to 1 when the CMake file is processed within ESP-IDF build system. Build/Project VariablesThe following are some project/build variables that are available as build properties and whose values can be queried using idfbuildgetpropertyfrom the component CMakeLists.txt:. PROJECTNAME: Name of the project, as set in project CMakeLists.txt file. PROJECTDIR: Absolute path of the project directory containing the project CMakeLists. Same as the CMAKESOURCEDIR variable.

COMPONENTS: Names of all components that are included in this build, formatted as a semicolon-delimited CMake list. IDFVER: Git version of ESP-IDF (produced by git describe). IDFVERSIONMAJOR, IDFVERSIONMINOR, IDFVERSIONPATCH: Components of ESP-IDF version, to be used in conditional expressions. Note that this information is less precise than that provided by IDFVER variable. V4.0-dev-., v4.0-beta1, v4.0-rc1 and v4.0 will all have the same values of IDFVERSION. variables, but different IDFVER values.

IDFTARGET: Name of the target for which the project is being built. PROJECTVER: Project version. If PROJECTVER variable is set in project CMakeLists.txt file, its value will be used.

Else, if the PROJECTDIR/version.txt exists, its contents will be used as PROJECTVER. Else, if the project is located inside a Git repository, the output of git describe will be used. Otherwise, PROJECTVER will be “1”.Other build properties are listed.

Idfcomponentregister (. REQUIRES mbedtls PRIVREQUIRES console spiffs ).

REQUIRES should be set to all components whose header files are #included from the public header files of this component. PRIVREQUIRES should be set to all components whose header files are #included from any source files in this component, unless already listed in REQUIRES. Also any component which is required to be linked in order for this component to function correctly. The values of REQUIRES and PRIVREQUIRES should not depend on any configuration choices ( CONFIGxxx macros). This is because requirements are expanded before configuration is loaded.

Other component variables (like include paths or source files) can depend on configuration choices. Not setting either or both REQUIRES variables is fine. If the component has no requirements except for the needed for RTOS, libc, etc.If a components only supports some target chips (values of IDFTARGET) then it can specify REQUIREDIDFTARGETS in the idfcomponentregister call to express these requirements. In this case the build system will generate an error if the component is included into the build, but does not support the selected target.

Idfcomponentregister ( SRCS 'car.c' INCLUDEDIRS '.' REQUIRES engine ). SRCS gives the list of source files in the car component. INCLUDEDIRS gives the list of public include directories for this component.

Because the public interface is car.h, the directory containing car.h is listed here. REQUIRES gives the list of components required by the public interface of this component.

Because car.h is a public header and includes a header from engine, we include engine here. This makes sure that any other component which includes car.h will be able to recursively include the required engine.h also. Including components in the build. By default, every component is included in the build. If you set the COMPONENTS variable to a minimal list of components used directly by your project, then the build will expand to also include required components.

The full list of components will be:. Components mentioned explicitly in COMPONENTS. Those components’ requirements (evaluated recursively). The “common” components that every component depends on. Setting COMPONENTS to the minimal list of required components can significantly reduce compile times. Requirements in the build system implementation.

Very early in the CMake configuration process, the script expandrequirements.cmake is run. This script does a partial evaluation of all component CMakeLists.txt files and builds a graph of component requirements (this graph may have cycles). The graph is used to generate a file componentdepends.cmake in the build directory. The main CMake process then includes this file and uses it to determine the list of components to include in the build (internal BUILDCOMPONENTS variable). The BUILDCOMPONENTS variable is sorted so dependencies are listed first, however as the component dependency graph has cycles this cannot be guaranteed for all components. The order should be deterministic given the same set of components and component dependencies.

The value of BUILDCOMPONENTS is logged by CMake as “Component names: “. Configuration is then evaluated for the components included in the build. Each component is included in the build normally and the CMakeLists.txt file is evaluated again to add the component libraries to the build.

Projectinclude.cmakeFor components that have build requirements which must be evaluated before any component CMakeListsfiles are evaluated, you can create a file called projectinclude.cmake in thecomponent directory. This CMake file is included when project.cmake is evaluating the entire project.projectinclude.cmake files are used inside ESP-IDF, for defining project-wide build features such as esptool.py command line arguments and the bootloader “special app”.Unlike component CMakeLists.txt files, when including a projectinclude.cmake file the current source directory ( CMAKECURRENTSOURCEDIR and working directory) is the project directory.

Use the variable COMPONENTDIR for the absolute directory of the component.Note that projectinclude.cmake isn’t necessary for the most common component uses - such as adding include directories to the project, or LDFLAGS to the final linking step. These values can be customised via the CMakeLists.txt file itself. See for details.projectinclude.cmake files are included in the order given in BUILDCOMPONENTS variable (as logged by CMake). This means that a component’s projectinclude.cmake file will be included after it’s all dependencies’ projectinclude.cmake files, unless both components are part of a dependency cycle. This is important if a projectinclude.cmake file relies on variables set by another component. See also.Take great care when setting variables or targets in a projectinclude.cmake file.

As the values are included into the top-level project CMake pass, they can influence or break functionality across all components! KConfig.projbuildThis is an equivalent to projectinclude.cmake for KConfig files. If you want to includeconfiguration options at the top-level of menuconfig, rather than inside the “Component Configuration” sub-menu, then these can be defined in the KConfig.projbuild file alongside the CMakeLists.txt file.Take care when adding configuration values in this file, as they will be included across the entire project configuration.

Cmake Tutorial

Where possible, it’s generally better to create a KConfig file for.projectinclude.cmake files are used inside ESP-IDF, for defining project-wide build features such as esptool.py command line arguments and the bootloader “special app”. Debugging CMakeFor full details about and CMake commands, see the.Some tips for debugging the ESP-IDF CMake-based build system:. When CMake runs, it prints quite a lot of diagnostic information including lists of components and component paths. Running cmake -DDEBUG=1 will produce more verbose diagnostic output from the IDF build system. Running cmake with the -trace or -trace-expand options will give a lot of information about control flow. See the.When included from a project CMakeLists file, the project.cmake file defines some utility modules and global variables and then sets IDFPATH if it was not set in the system environment.It also defines an overridden custom version of the built-in project function.

This function is overridden to add all of the ESP-IDF specific project functionality. Extern const uint8t serverrootcertpemstart asm ( 'binaryserverrootcertpemstart' ); extern const uint8t serverrootcertpemend asm ( 'binaryserverrootcertpemend' );The names are generated from the full name of the file, as given in EMBEDFILES. Characters /,., etc. Are replaced with underscores. The binary prefix in the symbol name is added by objcopy and is the same for both text and binary files.To embed a file into a project, rather than a component, you can call the function targetaddbinarydata like this.

Have the external BUILDCOMMAND run a full clean compile of all sources. The build command will be run if any of the dependencies passed to externalprojectadd with DEPENDS have changed, or if this is a clean build (ie any of idf.py clean, ninja clean, or make clean was run.). Have the external BUILDCOMMAND be an incremental build command.

Pass the parameter BUILDALWAYS 1 to externalprojectadd. This means the external project will be built each time a build is run, regardless of dependencies. This is only recommended if the external project has correct incremental build behaviour, and doesn’t take too long to run.The best of these approaches for building an external project will depend on the project itself, its build system, and whether you anticipate needing to frequently recompile the project. Custom sdkconfig defaultsFor example projects or other projects where you don’t want to specify a full sdkconfig configuration, but you do want to override some key values from the ESP-IDF defaults, it is possible to create a file sdkconfig.defaults in the project directory.

This file will be used when creating a new config from scratch, or when any new config value hasn’t yet been set in the sdkconfig file.To override the name of this file or to specify multiple files, set the SDKCONFIGDEFAULTS environment variable or set SDKCONFIGDEFAULTS in top-level CMakeLists.txt. If specifying multiple files, use semicolon as the list separator. File names not specified as full paths are resolved relative to current project.

Target-dependent sdkconfig defaultsIn addition to sdkconfig.defaults file, build system will also load defaults from sdkconfig.defaults.TARGETNAME file, where TARGETNAME is the value of IDFTARGET. For example, for esp32 target, default settings will be taken from sdkconfig.defaults first, and then from sdkconfig.defaults.esp32.If SDKCONFIGDEFAULTS is used to override the name of defaults file/files, the name of target-specific defaults file will be derived from SDKCONFIGDEFAULTS value/values using the rule above. Flash argumentsThere are some scenarios that we want to flash the target board without IDF. For this case we want to save the built binaries, esptool.py and esptool writeflash arguments. It’s simple to write a script to save binaries and esptool.py.After running a project build, the build directory contains binary output files (.bin files) for the project and also the following flashing data files:. flashprojectargs contains arguments to flash the entire project (app, bootloader, partition table, PHY data if this is configured).

flashappargs contains arguments to flash only the app. flashbootloaderargs contains arguments to flash only the bootloader.You can pass any of these flasher argument files to esptool.py as follows. Building the BootloaderThe bootloader is built by default as part of idf.py build, or can be built standalone via idf.py bootloader.The bootloader is a special “subproject” inside. It has its own project CMakeLists.txt file and builds separate.ELF and.BIN files to the main project. However it shares its configuration and build directory with the main project.The subproject is inserted as an external project from the top-level project, by the file. The main build process runs CMake for the subproject, which includes discovering components (a subset of the main components) and generating a bootloader-specific config (derived from the main sdkconfig). Addlibrary ( json STATIC cJSON/cJSON.c cJSON/cJSONUtils.c ) targetincludedirectories ( json PUBLIC cJSON ).

This is actually an equivalent declaration to the IDF json component. This file is quite simple as there are not a lot of source files. For components with a large number of files, the globbing behaviour of ESP-IDF’s component logic can make the component CMakeLists style simpler.). Any time a component adds a library target with the component name, the ESP-IDF build system will automatically add this to the build, expose public include directories, etc. If a component wants to add a library target with a different name, dependencies will need to be added manually via CMake commands. Using Third-Party CMake Projects with ComponentsCMake is used for a lot of open-source C and C projects — code that users can tap into for their applications.

One of the benefits of having a CMake build systemis the ability to import these third-party projects, sometimes even without modification! This allows for users to be able to get functionality that maynot yet be provided by a component, or use another library for the same functionality.Importing a library might look like this for a hypothetical library foo to be used in the main component. # Register the component idfcomponentregister (. ) # Set values of hypothetical variables that control the build of `foo` set ( FOOBUILDSTATIC OFF ) set ( FOOBUILDTESTS OFF ) # Create and import the library targets addsubdirectory ( foo ) # Publicly link `foo` to `main` component targetlinklibraries ( main PUBLIC foo )For an actual example, take a look at. Take note that what needs to be done in order to importthe library may vary.

It is recommended to read up on the library’s documentation for instructions on how toimport it from other projects. Studying the library’s CMakeLists.txt and build structure can also be helpful.It is also possible to wrap a third-party library to be used as a component in this manner.

Cmake File

For example, the component is a wrapper forEspressif’s fork of. See its.The CMake variable ESPPLATFORM is set to 1 whenever the ESP-IDF build system is being used. Tests such as if (ESPPLATFORM) can be used in generic CMake code if special IDF-specific logic is required. Idfbuildprocess(targetPROJECTDIR projectdirPROJECTVER projectverPROJECTNAME projectnameSDKCONFIG sdkconfigSDKCONFIGDEFAULTS sdkconfigdefaultsBUILDDIR builddirCOMPONENTS component1 component2.)Performs the bulk of the behind-the-scenes magic for including ESP-IDF components such as component configuration, libraries creation,dependency expansion and resolution. Among these functions, perhaps the most importantfrom a user’s perspective is the libraries creation by calling each component’s idfcomponentregister.

This command creates the libraries for each component, which are accessible using aliases in the formidf:: componentname. These aliases can be used to link the components to the user’s own targets, either librariesor executables.The call requires the target chip to be specified with target argument. Optional arguments for the call include:.

PROJECTDIR - directory of the project; defaults to CMAKESOURCEDIR. PROJECTNAME - name of the project; defaults to CMAKEPROJECTNAME.

PROJECTVER - version/revision of the project; defaults to “1”. SDKCONFIG - output path of generated sdkconfig file; defaults to PROJECTDIR/sdkconfig or CMAKESOURCEDIR/sdkconfig depending if PROJECTDIR is set. SDKCONFIGDEFAULTS - list of files containing default config to use in the build (list must contain full paths); defaults to empty. For each value filename in the list, the config from file filename.target, if it exists, is also loaded.

BUILDDIR - directory to place ESP-IDF build-related artifacts, such as generated binaries, text files, components; defaults to CMAKEBINARYDIR. COMPONENTS - select components to process among the components known by the build system (added via idfbuildcomponent).

This argument is used to trim the build.Other components are automatically added if they are required in the dependency chain, i.e.the public and private requirements of the components in this list are automatically added, and in turn the public and private requirements of those requirements,so on and so forth. If not specified, all components known to the build system are processed. Idfcomponentregister(SRCS src1 src2. SRCDIRS dir1 dir2. EXCLUDESRCS src1 src2.INCLUDEDIRS dir1 dir2.PRIVINCLUDEDIRS dir1 dir2.REQUIRES component1 component2.PRIVREQUIRES component1 component2.LDFRAGMENTS ldfragment1 ldfragment2.REQUIREDIDFTARGETS target1 target2.EMBEDFILES file1 file2.EMBEDTXTFILES file1 file2.)Register a component to the build system. Much like the project CMake command, this should be called from the component’sCMakeLists.txt directly (not through a function or macro) and is recommended to be called before any other command. Here are someguidelines on what commands can not be called before idfcomponentregister.

SRCS - component source files used for creating a static library for the component; if not specified, component is a treated as aconfig-only component and an interface library is created instead. SRCDIRS, EXCLUDESRCS - used to glob source files (.c,.cpp,.S) by specifying directories, instead of specifying source files manually via SRCS.

Note that this is subject to the. Idf-component-propertiesThese are properties that describe a component.

Idfcomponentregister ( SRCDIRS library platform. )This uses globbing behind the scenes to find source files in the specified directories. Be aware, however, that if a new source file is added and this method is used, then CMake won’t know to automatically re-run and this file won’t be added to the build.The trade-off is acceptable when you’re adding the file yourself, because you can trigger a clean build or run idf.py reconfigure to manually re-run. However, the problem gets harder when you share your project with others who may check out a new version using a source control tool like GitFor components which are part of ESP-IDF, we use a third party Git CMake integration module which automatically re-runs CMake any time the repository commit changes. Build System MetadataFor integration into IDEs and other build systems, when CMake runs the build process generates a number of metadata files in the build/ directory. To regenerate these files, run cmake or idf.py reconfigure (or any other idf.py build command). compilecommands.json is a standard format JSON file which describes every source file which is compiled in the project.

A CMake feature generates this file, and many IDEs know how to parse it. projectdescription.json contains some general information about the ESP-IDF project, configured paths, etc. flasherargs.json contains esptool.py arguments to flash the project’s binary files. There are also flash.args files which can be used directly with esptool.py. See. CMakeCache.txt is the CMake cache file which contains other information about the CMake process, toolchain, etc. config/sdkconfig.json is a JSON-formatted version of the project configuration values.

config/kconfigmenus.json is a JSON-formatted version of the menus shown in menuconfig, for use in external IDE UIs. JSON Configuration ServerA tool called confserver.py is provided to allow IDEs to easily integrate with the configuration system logic. Confserver.py is designed to run in the background and interact with a calling process by reading and writing JSON over process stdin & stdout.You can run confserver.py from a project via idf.py confserver or ninja confserver, or a similar target triggered from a different build generator.The config server outputs human-readable errors and warnings on stderr and JSON on stdout. On startup, it will output the full values of each configuration item in the system as a JSON dictionary, and the available ranges for values which are range constrained. The same information is contained in sdkconfig.json. build.cmake - Build related commands i.e. Build initialization, retrieving/setting build properties, build processing.

component.cmake - Component related commands i.e. Adding components, retrieving/setting component properties, registering components. kconfig.cmake - Generation of configuration files (sdkconfig, sdkconfig.h, sdkconfig.cmake, etc.) from Kconfig files.

ldgen.cmake - Generation of final linker script from linker fragment files. target.cmake - Setting build target and toolchain file. utilities.cmake - Miscellaneous helper commands.Aside from these files, there are two other important CMake scripts in. Upon inclusion of idf.cmake in project.cmake, the following steps are performed:.

Set IDFPATH from environment variable or inferred from path to project.cmake included in the top-level CMakeLists.txt. Add to CMAKEMODULEPATH and include core modules plus the various helper/third-party scripts. Set build tools/executables such as default Python interpreter, mconf, etc. Get ESP-IDF git revision and store as IDFVER. Set global build specifications i.e. Compile options, compile definitions, include directories for all components in the build. Add components in to the build.

The initial part of the custom project command performs the following steps:. Set IDFTARGET from environment variable or CMake cache and the corresponding CMAKETOOLCHAINFILE to be used. Add components in EXTRACOMPONENTSDIRS to the build. Prepare arguments for calling command idfbuildprocess from variables such as COMPONENTS/ EXCLUDECOMPONENTS, SDKCONFIG, SDKCONFIGDEFAULTS.The call to idfbuildprocess command marks the end of this phase.

This phase processes the components in the build, and is the second half of idfbuildprocess. Load project configuration from sdkconfig file and generate an sdkconfig.cmake and sdkconfig.h header.

These define configuration variables/macros that are accessible from the build scripts and C/C source/header files, respectively. Include each component’s projectinclude.cmake. Add each component as a subdirectory, processing its CMakeLists.txt. The component CMakeLists.txt calls the registration command, idfcomponentregister which adds source files, include directories, creates component library, links dependencies, etc.

$IDFPATH/tools/cmake/converttocmake.py /path/to/projectdirThe project directory must contain a Makefile, and GNU Make ( make) must be installed and available on the PATH.The tool will convert the project Makefile and any component component.mk files to their equivalent CMakeLists.txt files.It does so by running make to expand the ESP-IDF build system variables which are set by the build, and then producing equivalent CMakelists files to set the same variables.The conversion tool is not capable of dealing with complex Makefile logic or unusual targets. These will need to be converted by hand.

No Longer Available in CMakeSome features are significantly different or removed in the CMake-based system. The following variables no longer exist in the CMake-based build system:. COMPONENTBUILDDIR: Use CMAKECURRENTBINARYDIR instead.

COMPONENTLIBRARY: Defaulted to $(COMPONENTNAME).a, but the library name could be overriden by the component. The name of the component library can no longer be overriden by the component. CC, LD, AR, OBJCOPY: Full paths to each tool from the gcc xtensa cross-toolchain.

Use CMAKECCOMPILER, CMAKECLINKEXECUTABLE, CMAKEOBJCOPY, etc instead. HOSTCC, HOSTLD, HOSTAR: Full names of each tool from the host native toolchain. These are no longer provided, external projects should detect any required host toolchain manually. COMPONENTADDLDFLAGS: Used to override linker flags. Use the CMake command instead. COMPONENTADDLINKERDEPS: List of files that linking should depend on.

Will usually infer these dependencies automatically. For linker scripts, use the provided custom CMake function targetlinkerscripts. COMPONENTSUBMODULES: No longer used, the build system will automatically enumerate all submodules in the ESP-IDF repository. COMPONENTEXTRAINCLUDES: Used to be an alternative to COMPONENTPRIVINCLUDEDIRS for absolute paths. Use PRIVINCLUDEDIRS argument to idfcomponentregister for all cases now (can be relative or absolute).

COMPONENTOBJS: Previously, component sources could be specified as a list of object files. Now they can be specified as a list of source files via SRCS argument to idfcomponentregister.

COMPONENTOBJEXCLUDE: Has been replaced with EXCLUDESRCS argument to idfcomponentregister. Specify source files (as absolute paths or relative to component directory), instead. COMPONENTEXTRACLEAN: Set property ADDITIONALMAKECLEANFILES instead but note. COMPONENTOWNBUILDTARGET & COMPONENTOWNCLEANTARGET: Use CMake instead. See for full details. COMPONENTCONFIGONLY: Call idfcomponentregister without any arguments instead.

See. CFLAGS, CPPFLAGS, CXXFLAGS: Use equivalent CMake commands instead.