Do not fully defragment the shell statements in makefile (mainly for utility only)

1. Some common functions

Wildcard wildcard is a pattern matching function, the function model is roughly $ (wildcard parameter), the function's return value is the file that is actually found after the match, or other, depending on the argument, for example, using a statement in the shell C_source = $ ( Wildcard%.c), then the value of C_source is the collection of all. c files in the same folder as the current makefile file.

Patsubst Patsubst is a function of pattern substitution, and unlike wildcard, this function can replace some characters in a dictation string in some format, whose function model is $ (patsubst arg1, arg2, TEXT) For example, In the shell we often use c_objs= (Patsubst (Patsubst%.c,%.o, (C_source)), then the return of the function to the C_OBJS value is, will C_ All the files in source that end in the. c format are replaced with the. o Format

. Phony this is a special keyword, the characterization is followed by the target file, in the console when using certain commands, do not check for the existence of files to be processed, commonly used in the life of clean this action in the shell statement such as the use of a sentence, such as. Phony:clean, when you perform a clean command on the console, you do not check to see if the target file to clean is present.

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