${LDS_FILE} what is the difference between { and ( in makefile?

In a Makefile, `{}` and `()` have different meanings.

- `{}` is used for creating a shell command block. This is used when you want to execute multiple commands in a single shell instance. For example:

  target:
  	{ \
  		echo "Command 1"; \
  		echo "Command 2"; \
  	}

- `()` is used for defining dependencies. This is used when you want to group multiple dependencies together. For example:

  target: dependency1 (dependency2 dependency3)
  	commands

In this example, `dependency2` and `dependency3` are grouped together using `()`. They are treated as a single dependency, and `commands` will only be executed if all dependencies are up-to-date.

相关问题

${LDS_FILE} what is the difference between { and ( ?

In programming, the curly brace `{}` is typically used to enclose a block of code, such as in functions, loops, and conditional statements. On the other hand, parenthesis `()` are often used to enclose arguments in function calls or mathematical expressions.

For example, in C++ or Java, a function definition might look like this:

int myFunction(int arg1, int arg2) {
    // code block enclosed in curly braces
    int result = arg1 + arg2;
    return result;
}

In this example, the curly braces define the beginning and end of the function's code block.

In contrast, a function call might look like this:

int x = myFunction(3, 5);

In this example, the arguments `3` and `5` are enclosed in parentheses, indicating that they are being passed as arguments to the `myFunction` function.

$(call if_changed_dep,cpp_lds_S) is cpp_lds_S the argument fot if_changed_deo?

Yes, in the expression `$(call if_changed_dep,cpp_lds_S)`, `cpp_lds_S` is the argument for the `if_changed_dep` function.

The `if_changed_dep` function is a built-in function in Makefile that is used to run a command only if its dependencies have changed. The syntax for using `if_changed_dep` is:

$(if_changed_dep,command)

Here, `command` is the shell command that you want to run if its dependencies have changed.

In your example, `cpp_lds_S` is being passed as an argument to `if_changed_dep`. This means that `cpp_lds_S` is the command that will be executed by `if_changed_dep` if its dependencies have changed.

So, the `if_changed_dep` function will check if the dependencies of the target that is being built have changed since the last build, and if they have, it will execute the `cpp_lds_S` command. If the dependencies have not changed, `cpp_lds_S` will not be executed.