Question

我正在尝试交叉编译libftdi for arm。当我运行Cmake时，我得到：

CMake Error: The following variables are used in this project, but they are set to NOTFOUND.
Please set them or make sure they are set and tested correctly in the CMake files:
LIBUSB_INCLUDE_DIR (ADVANCED)

我知道LIBUSB_INCLUDE_DIR应该在libftdi根目录中找到的FindUSB1.cmake中设置。但是，我不知道如何使FindUSB1.cmake找到我已编译并放入/ opt / lib的libusb。这是默认文件：

# - Try to find the freetype library
# Once done this defines
#
#  LIBUSB_FOUND - system has libusb
#  LIBUSB_INCLUDE_DIR - the libusb include directory
#  LIBUSB_LIBRARIES - Link these to use libusb

# Copyright (c) 2006, 2008  Laurent Montel, <montel@kde.org>
#
# Redistribution and use is allowed according to the terms of the BSD license.
# For details see the accompanying COPYING-CMAKE-SCRIPTS file.


if (LIBUSB_INCLUDE_DIR AND LIBUSB_LIBRARIES)

  # in cache already
  set(LIBUSB_FOUND TRUE)

else (LIBUSB_INCLUDE_DIR AND LIBUSB_LIBRARIES)
  IF (NOT WIN32)
    # use pkg-config to get the directories and then use these values
    # in the FIND_PATH() and FIND_LIBRARY() calls

    find_package(PkgConfig)
    pkg_check_modules(PC_LIBUSB libusb-1.0)
  ENDIF(NOT WIN32)

  FIND_PATH(LIBUSB_INCLUDE_DIR libusb.h
    PATHS ${PC_LIBUSB_INCLUDEDIR} ${PC_LIBUSB_INCLUDE_DIRS})

  FIND_LIBRARY(LIBUSB_LIBRARIES NAMES usb-1.0
    PATHS ${PC_LIBUSB_LIBDIR} ${PC_LIBUSB_LIBRARY_DIRS})

  include(FindPackageHandleStandardArgs)
  FIND_PACKAGE_HANDLE_STANDARD_ARGS(LIBUSB DEFAULT_MSG LIBUSB_LIBRARIES LIBUSB_INCLUDE_DIR)

  MARK_AS_ADVANCED(LIBUSB_INCLUDE_DIR LIBUSB_LIBRARIES)

endif (LIBUSB_INCLUDE_DIR AND LIBUSB_LIBRARIES)

在/ opt / lib中有一个目录pkconfig。在这个目录中有一个libusb-1.0.pc文件，我想这可能与该问题有关。那么我该如何让Cmake找到/opt/lib/libsub-1.0？

Answer 1

不幸的是，默认的find脚本不是很强大。如果该库未位于find_library pkg-config搜索的one of the default directories内，您必须依靠pkg-config来告诉您该库的位置。

在库中未注册PC_LIBUSB_LIBDIR的（不是那么不可能）事件中，除了在调用查找脚本之前手动设置PC_LIBUSB_INCLUDEDIR和HINTS变量之外别无选择。这可以通过命令行（使用-D parameter）或封闭的CMake脚本（使用set）完成。

如果您可以自由更改查找脚本，请考虑在查找调用中添加其他FIND_PATH(LIBUSB_INCLUDE_DIR libusb.h HINTS $ENV{LIBUSB_ROOT} PATHS ${PC_LIBUSB_INCLUDEDIR} ${PC_LIBUSB_INCLUDE_DIRS} PATH_SUFFIXES include) FIND_LIBRARY(LIBUSB_LIBRARIES NAMES usb-1.0 HINTS $ENV{LIBUSB_ROOT} PATHS ${PC_LIBUSB_LIBDIR} ${PC_LIBUSB_LIBRARY_DIRS} PATH_SUFFIXES lib)以使其更灵活。例如，使用环境变量作为提示是一种非常流行的机制，也适用于非Unix平台。

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如何设置LIBUSB_INCLUDE_DIR

1 个答案: