Add macros cmake_push/pop_check_state() as discussed on the list.

This patch adds two macros cmake_push_check_state() and
cmake_pop_check_state(), which can be used to save and restore
the contents of the CMAKE_REQUIRED_xxx variables.

Alex

1 files changed, 52 insertions, 0 deletions

diff --git a/Modules/CMakePushCheckState.cmake b/Modules/CMakePushCheckState.cmake
new file mode 100644
index 0000000..52503e5
--- /dev/null
+++ b/Modules/CMakePushCheckState.cmake
@@ -0,0 +1,52 @@
+# This module defines two macros:
+# CMAKE_PUSH_CHECK_STATE()
+# and
+# CMAKE_POP_CHECK_STATE()
+# These two macros can be used to save and restore the state of the variables
+# CMAKE_REQUIRED_FLAGS, CMAKE_REQUIRED_DEFINITIONS, CMAKE_REQUIRED_LIBRARIES
+# and CMAKE_REQUIRED_INCLUDES used by the various Check-files coming with CMake,
+# like e.g. check_function_exists() etc.
+# The variable contents are pushed on a stack, pushing multiple times is supported.
+# This is useful e.g. when executing such tests in a Find-module, where they have to be set,
+# but after the Find-module has been executed they should have the same value
+# as they had before.
+#
+# Usage:
+#   cmake_push_check_state()
+#   set(CMAKE_REQUIRED_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS} -DSOME_MORE_DEF)
+#   check_function_exists(...)
+#   cmake_pop_check_state()
+
+# Copyright (c) 2006-2011, Alexander Neundorf, <neundorf@kde.org>
+#
+# Redistribution and use is allowed according to the terms of the BSD license.
+# For details see the accompanying COPYING-CMAKE-SCRIPTS file.
+
+MACRO(CMAKE_PUSH_CHECK_STATE)
+
+   IF(NOT DEFINED _CMAKE_PUSH_CHECK_STATE_COUNTER)
+      SET(_CMAKE_PUSH_CHECK_STATE_COUNTER 0)
+   ENDIF()
+
+   MATH(EXPR _CMAKE_PUSH_CHECK_STATE_COUNTER "${_CMAKE_PUSH_CHECK_STATE_COUNTER}+1")
+
+   SET(_CMAKE_REQUIRED_INCLUDES_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER}    ${CMAKE_REQUIRED_INCLUDES})
+   SET(_CMAKE_REQUIRED_DEFINITIONS_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER} ${CMAKE_REQUIRED_DEFINITIONS})
+   SET(_CMAKE_REQUIRED_LIBRARIES_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER}   ${CMAKE_REQUIRED_LIBRARIES})
+   SET(_CMAKE_REQUIRED_FLAGS_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER}       ${CMAKE_REQUIRED_FLAGS})
+ENDMACRO(CMAKE_PUSH_CHECK_STATE)
+
+MACRO(CMAKE_POP_CHECK_STATE)
+
+# don't pop more than we pushed
+   IF("${_CMAKE_PUSH_CHECK_STATE_COUNTER}" GREATER "0")
+
+      SET(CMAKE_REQUIRED_INCLUDES    ${_CMAKE_REQUIRED_INCLUDES_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER}})
+      SET(CMAKE_REQUIRED_DEFINITIONS ${_CMAKE_REQUIRED_DEFINITIONS_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER}})
+      SET(CMAKE_REQUIRED_LIBRARIES   ${_CMAKE_REQUIRED_LIBRARIES_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER}})
+      SET(CMAKE_REQUIRED_FLAGS       ${_CMAKE_REQUIRED_FLAGS_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER}})
+
+      MATH(EXPR _CMAKE_PUSH_CHECK_STATE_COUNTER "${_CMAKE_PUSH_CHECK_STATE_COUNTER}-1")
+   ENDIF()
+
+ENDMACRO(CMAKE_POP_CHECK_STATE)