--- name: "zmk.Toolchain" section: "5" platform: "linux" package: "zmk-doc" version: "0.5.1-2" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/zmk.Toolchain" --- # zmk.Toolchain(5) module providing information and configuration about compiler toolchain ## NAME **Toolchain** – module providing information and configuration about compiler toolchain ## SYNOPSIS ``` include z.mk $(eval $(call ZMK.Import,Toolchain)) ``` ## DESCRIPTION The **Toolchain** module encapsulates information about the used C and C++ compilers. This knowledge is mainly consumed internally by other modules and templates, but can be used directly to construct custom rules. ## TARGETS This module does not provide any targets. ## VARIABLES This module provides the following variables. Please take note that make supports *target-specific* *variables*, where a specific variable, for example **CFLAGS** or **LDLIBS** takes a particular value only while building a specific target as well as all the targets that it depends on. This scheme is removes the need for additional variables manually customized to a specific target. ### CC The C compiler. ### CPP The pre-processor, responsible for macros and include directives. ### CXX The C++ compiler. ### CFLAGS Configuration options for the C compiler. This variable should be used to pass options such as *-Wall*, *-O2*, or *-fpic*. Please refer to your compiler manual for details. This variable is often abused, mainly for simplicity, as a kitchen-sink that holds all of the compiler and linker options. This is discouraged. ### CPPFLAGS Configurations options for the pre-processor. This variable should be used to provide command line options that alter the include search path, such as *-I*, or define a pre-processor macro, such as *-D*. ### CXXFLAGS Configuration options for the C++ compiler. This variable the equivalent of **CFLAGS** for the C++ compiler. ### OBJCFLAGS Configuration options for the Objective C compiler. This variable the equivalent of **CFLAGS** for the Objective C compiler. ### ARFLAGS Configuration options for the **ar** program. ### TARGET\_ARCH Compiler options for performing architecture selection. This variable is not used by zmk. Cross compilation is supported by selecting a cross-compiling **CC** or **CXX**. ### LDLIBS Additional libraries to link with. Libraries are provided in the form *-lfoo* where *foo* is the name of the library, without the prefix *lib*. Given the choice of static and dynamic libraries, the linker will prefer dynamic linking. You can a specific library statically with the following option sequence. *-Wl,-dn* *-lfoo* *-Wl,-dy*. The first segment *-Wl,-dn* turns off dynamic linking *-lfoo* links to the library *libfoo.a* while the final *-Wl,-dy* turns dynamic linking back again. Note that using this sequence the final executable is not entirely statically linked. If *libfoo.a* has any additional dependences those must be linked as well, either dynamically or statically. ### LDFLAGS Configuration options for the linker. This variable should be used to provide command line options that alter the linker search path, such as *-L*, or customize linker behavior. Note that the linker is not invoked directly, but through the compiler front-end. For example, when using gcc, one would typically pass *-Wl,foo* in order to pass the option *foo* to the linker. ### exe The suffix for executables. It is either empty or has the value *.exe*, if the *image* *format* of the resulting executable is either **PE** or **MZ**. This variable is automatically used by zmk when building executables. ### Toolchain.SysRoot Path of the root directory where the compiler looks for headers and libraries. A non-empty value causes *--sysroot=$(Toolchain.SysRoot)* to be passed to the compiler whenever it is used for compiling, linking or pre-processing. The default value is *$(Configure.SysRoot)*, namely the preference from the configuration system. ### Toolchain.DependencyTracking Expands to *yes*, if compilation of C, C++ and Objective C source files will automatically generate dependency rules for Make. The default value is *$(Configure.DependencyTracking)*, namely the preference from the configuration system. ### Toolchain.ImageFormat Identifier or the application image format generated by *both* the C compiler or the C++ compiler. If the two compilers produce different image formats, for example because one is a *cross-compiler* the effective value is *Mixed*. ### Toolchain.IsCross Expands to *yes* if programs created by *either* the C compiler or the C++ compiler cannot be executed on the machine performing the build. ### Toolchain.IsGcc Expands to *yes*, if both the C and C++ compilers are from the *GNU* *Compiler* *Collection*. ### Toolchain.IsClang Expands to *yes*, if both the C and C++ compilers are from the *clang* project. ### Toolchain.IsWatcom Expands to *yes*, if both the C and C++ compilers are from the *Open* *Watcom* compiler. ### Toolchain.CC.IsAvaiable Expands to *yes* if the C compiler is available. ### Toolchain.CC.ImageFormat Identifier or the application image format generated by the C compiler. Refer to the documentation of **OS.ImageFormat** for a description of known formats. Unless *cross-compiling*, the default value is *$(OS.ImageFormat)*. ### Toolchain.CC.IsCross Expands to *yes* if programs created by the C compiler cannot be executed on the machine performing the build. ### Toolchain.CC.IsGcc Expands to *yes*, if the selected C compiler is the *GNU* *Compiler* *Collection*. This variable, as well as several others documented below, can be used to conditionally enable compiler specific options in a manner that does not break when another compiler is used. ### Toolchain.CC.IsClang Expands to *yes*, if the selected C compiler is *clang*. ### Toolchain.CC.IsWatcom Expands to *yes*, if the selected C compiler is the *Open* *Watcom* compiler. ### Toolchain.CC.IsTcc Expands to *yes*, if the selected C compiler is the *Tiny* *C* *Compiler*. ### Toolchain.CXX.IsAvaiable Expands to *yes* if the C++ compiler is available. ### Toolchain.CXX.ImageFormat Identifier or the application image format generated by the C++ compiler. Unless *cross-compiling*, the default value is *$(OS.ImageFormat)*. ### Toolchain.CXX.IsCross Expands to *yes* if programs created by the C++ compiler cannot be executed on the machine performing the build. ### Toolchain.CXX.IsGcc Expands to *yes*, if the selected C++ compiler is the *GNU* *Compiler* *Collection*. ### Toolchain.CXX.IsClang Expands to *yes*, if the selected C++ compiler is *clang*. ### Toolchain.CXX.IsWatcom Expands to *yes*, if the selected C++ compiler is the *Open* *Watcom* compiler. ## EXAMPLES ## HISTORY The **Toolchain** module first appeared in zmk 0.3 ## AUTHORS Zygmunt Krynicki ⟨*me@zygoon.pl*⟩