-MD -MP -MF $(depfile) -MT $@ -c -o $@ $< explain this command in detail please
时间: 2023-12-05 07:06:37 浏览: 31
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.