get_depfile_name = $(subst $(comma),_,$($(dir $(1)).$(notdir $(1))).d)
时间: 2023-12-17 15:02:30 浏览: 77
这段代码是定义了一个函数get_depfile_name,它的参数是$(1)。函数首先调用了dir函数获取$(1)中的目录部分,再调用notdir函数获取$(1)中的文件名部分,然后将这两部分以"."连接在一起,作为变量名进行展开,得到一个变量值,再将这个变量值中的逗号($(comma))替换成下划线(_),最后加上后缀".d",作为函数的返回值。因此,如果传入的$(1)是一个文件路径,get_depfile_name函数将返回该文件所在目录和文件名(去掉目录部分后)中间用"."连接的变量名,经过逗号替换后加上".d"后缀的结果。这个函数可能是用来生成一些特殊的依赖文件名。
相关问题
-MD -MP -MF $(depfile) -MT $@ -c -o $@ $< explain this command in detail please
Sure! This is a common command used in Makefiles to generate dependency files during the compilation process in C/C++ programming. Here is an explanation of each parameter:
- `-MD`: This parameter tells the compiler to generate dependency files in the Makefile format. These files are used to track dependencies between source files and header files.
- `-MP`: This parameter generates a phony target for each header file dependency, which ensures that the Makefile won't fail if a header file is deleted or renamed.
- `-MF $(depfile)`: This parameter specifies the name of the dependency file to be generated. The `$(depfile)` variable is typically defined earlier in the Makefile and contains the name and path of the dependency file.
- `-MT $@`: This parameter specifies the name of the target to be built. The `$@` variable represents the name of the target being built, which is typically an object file.
- `-c`: This parameter tells the compiler to generate an object file, but not to link it with other object files to create an executable.
- `-o $@`: This parameter specifies the name of the object file to be generated. The `$@` variable represents the name of the target being built, which is typically an object file.
- `$<`: This is a special variable that represents the name of the first prerequisite (dependency) of the target. In this case, it represents the name of the source file being compiled.
Here is an example command:
```
gcc -MD -MP -MF main.d -MT main.o -c -o main.o main.c
```
This command compiles the source file "main.c" into an object file named "main.o". It also generates a dependency file named "main.d" that tracks the dependencies between "main.c" and any included header files. The `$(depfile)` and `$@` variables are typically defined earlier in the Makefile.
GN depfile
GN depfile是Google开发的一种构建工具,用于生成构建系统所需的依赖文件。它是GN(Generate Ninja)构建系统的一部分,用于描述和管理项目的构建过程。
GN depfile主要用于记录源代码文件之间的依赖关系,以及构建过程中生成的中间文件和目标文件之间的依赖关系。通过分析这些依赖关系,构建系统可以确定哪些文件需要重新编译,从而提高构建效率。
GN depfile的格式通常是一个文本文件,每一行表示一个依赖关系。例如,一行可能表示某个源文件依赖于其他源文件或头文件,或者某个目标文件依赖于其他中间文件或源文件。
使用GN depfile可以帮助开发人员更好地管理项目的构建过程,减少不必要的重新编译,提高代码的构建效率。
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