Makefile Concise Guide (3 ))

Makefile Concise Guide (3) 2010/06/08 14:52

Target and dependent can also be a label rather than a file ). In this case, it is called "pseudo target ). The name of the pseudo target cannot be the same as any file name in the current directory. If a pseudo-dotarget is to be used as a dependent, it must appear as a target in a dependent line. When the pseudo target is used as the target, the associated commands block will be executed, and nmake will assign it a hypothetical time stamp. This time stamp is equal to the maximum time stamp in its dependents, or, if it does not have a dependent, it is equal to the current time. This hypothetical time stamp is used for validity evaluation when the pseudo target is used as the dependent. The biggest benefit of this feature is that you can allow nmake to construct multiple targets without listing each target in the nmake command line. For example: ALL: setenv project1.exe project2.exe Project1.exe: project1.obj Link project1; Project2.exe: project2.obj Link project2; Setenv: Set Lib = \ project \ Lib In the preceding example, there are two pseudo targets, one being all and the other being setenv. The first step is the setenvevaluation. The second step is the configuration environment variable lib. then, project1.exeand project2.exe are updated in sequence. Commands Block The second line starts to the next Dependent line Between Commands Block , Which provides Dependents Any one Time stamp Greater Target The sequence of commands to be executed ( Commadns Block It can also be empty. At this time, Nmake ). Command Line It must start with a blank space ( Dependent line On the contrary, Nmake This feature is used to distinguish the two. Dependent line And Commands Block There cannot be blank lines between the first statement (that is, there is nothing except a line break. Therefore, only one blank space or tab row is valid.Nmake Interpret it as NULL command ), But in Command lines There can be blank lines between them. Commands Block Each Command in can be any valid command in the console. In fact Commands Block As A Batch Processing file consisting of console command sequences. In additionCommands BlockYou can also add one or more so-called command modifiers (Command Modifier) To implement some additional control over the command. Command modifiers include the following:3Type: 1) @ command Remove allStdout. 2)-[number] command Turn off the check for the return value of this command. By default, if a command returns a non-0Value, thenNmakeThe execution will stop. However, if you add"-", ThenNmakeThe return value of this command is ignored. If-"Followed by an integer, thenNmakeAny return values greater than this integer are ignored. 3 )! Command If the command execution object is$ **Or$?(Both are pre-defined macros. The former indicates the correspondingDependent lineAllDependent, The latter indicates all RatioTargetHas a largerTime stampOfDependent), Then the "!" The modifier will execute the command on each independent file described by the two macros. NmakeSome syntaxes can be found inCommands BlockIndicates the correspondingDependent lineThe firstDependent. For example: Foo.exe: C: \ sample \ first. OBJ c: \ sample \ second. OBJ Link % s NmakeSet"Link % s"Is interpreted: Link c: \ sample \ first. OBJ If you change the command to"Link % | pff.exe", ThenNmakeIt is interpreted: Link c: \ sample \ first.exe % SIndicates the full file name,% | [Part] FIndicates a part of the file name,PartIt can be one or more of the following characters. IfPartNull,% | FAnd% SThe meanings are the same: 1) d: Drive letter; 2) P: Path; 3) f: Basic file name; 4) E: File Extension