find类指令

• find_file - This command is used to find a full path to a named file.

  A short-hand signature is:

  find_file(<VAR> name1 [path1 path2 ...])

  • VAR - 存储查找结果的变量;
  • name1 - 要查找的文件的名称;
  • path1 path2 ... - 指定默认查找路径之外的额外查找路径.

  CMAKE_INCLUDE_PATH - 用来指定find_file和find_path的额外查找路径; CMAKE_SYSTEM_INCLUDE_PATH - find_file和find_path的系统默认查找路径.

  This command is used to find a full path to a named file. A cache entry named by <VAR> is created to store the result of this command. If the full path to a file is found the result is stroed in the variable and the search will not be repeated unless the variable is cleared. If nothing is found, the result will be <VAR>-NOTFOUND, and the search will be attemped again the next time find_file is invoked with the same variable.

• find_path - This command is used to find a directory containing the named file.

  A short-hand signature is:

  find_path(VAR name1 [path1 path2 ...])

  find_path的用法和find_file类似, 只不过查找的是包含指定文件的文件夹.

• find_library - This command is used to find a library.

  A short-hand signature is:

  find_library(<VAR> name1 [path1 path2 ...])

  CMAKE_LIBRARY_PATH - 指定find_library的查找路径; CMAKE_SYSTEM_LIBRARY_PATH - find_library的系统默认查找路径.

• find_program - This command is used to find a program.

  A short-hand signature is:

  find_program(<VAR> name1 [path1 path2 ...])

  CMAKE_PROGRAM_PATH - 额外指定find_program的查找路径; CMAKE_SYSTEM_PROGRAM_PATH - find_program的系统默认查找路径.

总结:

find_file, find_path, find_library和find_program的功能用用法类似.

对于通常的使用:

• 第一个参数是一个用来存储查找结果的cache变量, 如果没有找到, 则相应的值为: <VAR>-NOTFOUND;
• 第二个参数是要查找的目标的名称;
• 第三个参数是可选的, 用来指定默认查找路径之外的额外查找路径.

它们的不同之处在于: 它们用来指定查找路径的环境变量不同, 系统默认的查找路径也不同.