clang:tldr:d59b3

The command clang -c ${input_source-c} is a command to compile C source code using the Clang compiler.

Here is a breakdown of the command:

• clang is the command to invoke the Clang compiler.
• -c is an option to tell Clang to generate object code instead of an executable. It stands for "compile only".
• ${input_source-c} is a form of variable substitution. It is used to retrieve the value of the variable input_source and substitute it in place, but with a fallback value of "c" if the variable is not set. The exact way this substitution works depends on the shell or script in which this command is used.

In essence, this command is used to compile a C source file into object code using the Clang compiler. The input source file is specified by the value of the input_source variable if it is set, otherwise, the filename will be "c".