Home Explore Help
Register Sign In
Apq
/
CMake
mirror of https://github.com/Kitware/CMake.git
1
0
Fork 0
Files Issues 0 Wiki
Tree: b85d3b66c6
Branches Tags
CMake
/
Help
/
manual
/
cmake-policies.7.rst

cmake-policies.7.rst 3.4 KB
History Raw

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122 
  1. .. cmake-manual-description: CMake Policies Reference
    2. 

  2. 

  3. cmake-policies(7)
    4. 

  4. *****************
    5. 

  5. 

  6. .. only:: html
    7. 

  7. 

  8.    .. contents::
    9. 

  9. 

  10. Introduction
    11. 

  11. ============
    12. 

  12. 

  13. Policies in CMake are used to preserve backward compatible behavior
    14. 

  14. across multiple releases.  When a new policy is introduced, newer CMake
    15. 

  15. versions will begin to warn about the backward compatible behavior.  It
    16. 

  16. is possible to disable the warning by explicitly requesting the OLD, or
    17. 

  17. backward compatible behavior using the :command:`cmake_policy` command.
    18. 

  18. It is also possible to request ``NEW``, or non-backward compatible behavior
    19. 

  19. for a policy, also avoiding the warning.  Each policy can also be set to
    20. 

  20. either ``NEW`` or ``OLD`` behavior explicitly on the command line with the
    21. 

  21. :variable:`CMAKE_POLICY_DEFAULT_CMP<NNNN>` variable.
    22. 

  22. 

  23. Note that policies are not reliable feature toggles.  A policy should
    24. 

  24. almost never be set to ``OLD``, except to silence warnings in an otherwise
    25. 

  25. frozen or stable codebase, or temporarily as part of a larger migration
    26. 

  26. path. The ``OLD`` behavior of each policy is undesirable and will be
    27. 

  27. replaced with an error condition in a future release.
    28. 

  28. 

  29. The :command:`cmake_minimum_required` command does more than report an
    30. 

  30. error if a too-old version of CMake is used to build a project.  It
    31. 

  31. also sets all policies introduced in that CMake version or earlier to
    32. 

  32. ``NEW`` behavior.  To manage policies without increasing the minimum required
    33. 

  33. CMake version, the :command:`if(POLICY)` command may be used:
    34. 

  34. 

  35. .. code-block:: cmake
    36. 

  36. 

  37.   if(POLICY CMP0990)
    38. 

  38.     cmake_policy(SET CMP0990 NEW)
    39. 

  39.   endif()
    40. 

  40. 

  41. This has the effect of using the ``NEW`` behavior with newer CMake releases which
    42. 

  42. users may be using and not issuing a compatibility warning.
    43. 

  43. 

  44. The setting of a policy is confined in some cases to not propagate to the
    45. 

  45. parent scope.  For example, if the files read by the :command:`include` command
    46. 

  46. or the :command:`find_package` command contain a use of :command:`cmake_policy`,
    47. 

  47. that policy setting will not affect the caller by default.  Both commands accept
    48. 

  48. an optional ``NO_POLICY_SCOPE`` keyword to control this behavior.
    49. 

  49. 

  50. The :variable:`CMAKE_MINIMUM_REQUIRED_VERSION` variable may also be used
    51. 

  51. to determine whether to report an error on use of deprecated macros or
    52. 

  52. functions.
    53. 

  53. 

  54. All Policies
    55. 

  55. ============
    56. 

  56. 

  57. .. toctree::
    58. 

  58.    :maxdepth: 1
    59. 

  59. 

  60.    /policy/CMP0000
    61. 

  61.    /policy/CMP0001
    62. 

  62.    /policy/CMP0002
    63. 

  63.    /policy/CMP0003
    64. 

  64.    /policy/CMP0004
    65. 

  65.    /policy/CMP0005
    66. 

  66.    /policy/CMP0006
    67. 

  67.    /policy/CMP0007
    68. 

  68.    /policy/CMP0008
    69. 

  69.    /policy/CMP0009
    70. 

  70.    /policy/CMP0010
    71. 

  71.    /policy/CMP0011
    72. 

  72.    /policy/CMP0012
    73. 

  73.    /policy/CMP0013
    74. 

  74.    /policy/CMP0014
    75. 

  75.    /policy/CMP0015
    76. 

  76.    /policy/CMP0016
    77. 

  77.    /policy/CMP0017
    78. 

  78.    /policy/CMP0018
    79. 

  79.    /policy/CMP0019
    80. 

  80.    /policy/CMP0020
    81. 

  81.    /policy/CMP0021
    82. 

  82.    /policy/CMP0022
    83. 

  83.    /policy/CMP0023
    84. 

  84.    /policy/CMP0024
    85. 

  85.    /policy/CMP0025
    86. 

  86.    /policy/CMP0026
    87. 

  87.    /policy/CMP0027
    88. 

  88.    /policy/CMP0028
    89. 

  89.    /policy/CMP0029
    90. 

  90.    /policy/CMP0030
    91. 

  91.    /policy/CMP0031
    92. 

  92.    /policy/CMP0032
    93. 

  93.    /policy/CMP0033
    94. 

  94.    /policy/CMP0034
    95. 

  95.    /policy/CMP0035
    96. 

  96.    /policy/CMP0036
    97. 

  97.    /policy/CMP0037
    98. 

  98.    /policy/CMP0038
    99. 

  99.    /policy/CMP0039
    100. 

  100.    /policy/CMP0040
    101. 

  101.    /policy/CMP0041
    102. 

  102.    /policy/CMP0042
    103. 

  103.    /policy/CMP0043
    104. 

  104.    /policy/CMP0044
    105. 

  105.    /policy/CMP0045
    106. 

  106.    /policy/CMP0046
    107. 

  107.    /policy/CMP0047
    108. 

  108.    /policy/CMP0048
    109. 

  109.    /policy/CMP0049
    110. 

  110.    /policy/CMP0050
    111. 

  111.    /policy/CMP0051
    112. 

  112.    /policy/CMP0052
    113. 

  113.    /policy/CMP0053
    114. 

  114.    /policy/CMP0054
    115. 

  115.    /policy/CMP0055
    116. 

  116.    /policy/CMP0056
    117. 

  117.    /policy/CMP0057
    118. 

  118.    /policy/CMP0058
    119. 

  119.    /policy/CMP0059
    120. 

  120.    /policy/CMP0060
    121. 

  121.    /policy/CMP0061
    122. 

  122.    /policy/CMP0062
    123.