Clflags

Clflags is a term used in some build systems and scripts to denote the collection of command-line options passed to a compiler or interpreter during the build process. It is not a formal standard, but appears in various makefiles and configuration scripts as a variable that holds compilation options separate from the tool choice itself. The concept helps organize and reuse flags across targets or configurations.

In practice, clflags is typically defined in a build script and appended to the compiler invocation. For example, a project might set clflags="-O2 -g -Wall" and then compile with a command like $(CC) $(CPPFLAGS) $(clflags) -c file.c. The contents of clflags often include optimization settings, include paths, macro definitions, and other language-specific options such as -I for include directories, -D for macros, and architecture flags like -march. The exact flags depend on the language and the compiler being used.

Clflags commonly coexists with other variables such as CFLAGS, CXXFLAGS, and CPPFLAGS. In many build systems, clflags is used as a project-specific alias or as a place to centralize flags that apply to a particular tool chain or target, while CFLAGS/CXXFLAGS govern language-specific compilation and LDFLAGS governs linking. Portability considerations arise because flag syntax and accepted options differ across compilers and platforms; for example, Windows compilers may use different prefixes or options than GCC on Unix-like systems.

See also: CFLAGS, CXXFLAGS, CPPFLAGS, LDFLAGS, make, Autotools, CMake.