diff options
Diffstat (limited to 'Modules/CheckSymbolExists.cmake')
-rw-r--r-- | Modules/CheckSymbolExists.cmake | 108 |
1 files changed, 63 insertions, 45 deletions
diff --git a/Modules/CheckSymbolExists.cmake b/Modules/CheckSymbolExists.cmake index 0969bc562..6f1afcfda 100644 --- a/Modules/CheckSymbolExists.cmake +++ b/Modules/CheckSymbolExists.cmake @@ -1,48 +1,60 @@ -# - Check if a symbol exists as a function, variable, or macro -# CHECK_SYMBOL_EXISTS(<symbol> <files> <variable>) -# -# Check that the <symbol> is available after including given header -# <files> and store the result in a <variable>. Specify the list -# of files in one argument as a semicolon-separated list. -# -# If the header files define the symbol as a macro it is considered -# available and assumed to work. If the header files declare the -# symbol as a function or variable then the symbol must also be -# available for linking. If the symbol is a type or enum value -# it will not be recognized (consider using CheckTypeSize or -# CheckCSourceCompiles). -# If the check needs to be done in C++, consider using CHECK_CXX_SYMBOL_EXISTS(), -# which does the same as CHECK_SYMBOL_EXISTS(), but in C++. -# -# The following variables may be set before calling this macro to -# modify the way the check is run: -# -# CMAKE_REQUIRED_FLAGS = string of compile command line flags -# CMAKE_REQUIRED_DEFINITIONS = list of macros to define (-DFOO=bar) -# CMAKE_REQUIRED_INCLUDES = list of include directories -# CMAKE_REQUIRED_LIBRARIES = list of libraries to link +# Distributed under the OSI-approved BSD 3-Clause License. See accompanying +# file Copyright.txt or https://cmake.org/licensing for details. -#============================================================================= -# Copyright 2003-2011 Kitware, Inc. -# -# Distributed under the OSI-approved BSD License (the "License"); -# see accompanying file Copyright.txt for details. -# -# This software is distributed WITHOUT ANY WARRANTY; without even the -# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. -# See the License for more information. -#============================================================================= -# (To distribute this file outside of CMake, substitute the full -# License text for the above reference.) +#[=======================================================================[.rst: +CheckSymbolExists +----------------- +Provides a macro to check if a symbol exists as a function, variable, +or macro in ``C``. +.. command:: check_symbol_exists + + :: + + check_symbol_exists(<symbol> <files> <variable>) + + Check that the ``<symbol>`` is available after including given header + ``<files>`` and store the result in a ``<variable>``. Specify the list + of files in one argument as a semicolon-separated list. + ``<variable>`` will be created as an internal cache variable. + +If the header files define the symbol as a macro it is considered +available and assumed to work. If the header files declare the symbol +as a function or variable then the symbol must also be available for +linking (so intrinsics may not be detected). +If the symbol is a type, enum value, or intrinsic it will not be recognized +(consider using :module:`CheckTypeSize` or :module:`CheckCSourceCompiles`). +If the check needs to be done in C++, consider using +:module:`CheckCXXSymbolExists` instead. + +The following variables may be set before calling this macro to modify +the way the check is run: + +``CMAKE_REQUIRED_FLAGS`` + string of compile command line flags +``CMAKE_REQUIRED_DEFINITIONS`` + list of macros to define (-DFOO=bar) +``CMAKE_REQUIRED_INCLUDES`` + list of include directories +``CMAKE_REQUIRED_LIBRARIES`` + list of libraries to link +``CMAKE_REQUIRED_QUIET`` + execute quietly without messages +#]=======================================================================] macro(CHECK_SYMBOL_EXISTS SYMBOL FILES VARIABLE) - _CHECK_SYMBOL_EXISTS("${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.c" "${SYMBOL}" "${FILES}" "${VARIABLE}" ) + if(CMAKE_C_COMPILER_LOADED) + _CHECK_SYMBOL_EXISTS("${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.c" "${SYMBOL}" "${FILES}" "${VARIABLE}" ) + elseif(CMAKE_CXX_COMPILER_LOADED) + _CHECK_SYMBOL_EXISTS("${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.cxx" "${SYMBOL}" "${FILES}" "${VARIABLE}" ) + else() + message(FATAL_ERROR "CHECK_SYMBOL_EXISTS needs either C or CXX language enabled") + endif() endmacro() macro(_CHECK_SYMBOL_EXISTS SOURCEFILE SYMBOL FILES VARIABLE) - if("${VARIABLE}" MATCHES "^${VARIABLE}$") + if(NOT DEFINED "${VARIABLE}" OR "x${${VARIABLE}}" STREQUAL "x${VARIABLE}") set(CMAKE_CONFIGURABLE_FILE_CONTENT "/* */\n") set(MACRO_CHECK_SYMBOL_EXISTS_FLAGS ${CMAKE_REQUIRED_FLAGS}) if(CMAKE_REQUIRED_LIBRARIES) @@ -58,16 +70,18 @@ macro(_CHECK_SYMBOL_EXISTS SOURCEFILE SYMBOL FILES VARIABLE) set(CMAKE_SYMBOL_EXISTS_INCLUDES) endif() foreach(FILE ${FILES}) - set(CMAKE_CONFIGURABLE_FILE_CONTENT - "${CMAKE_CONFIGURABLE_FILE_CONTENT}#include <${FILE}>\n") + string(APPEND CMAKE_CONFIGURABLE_FILE_CONTENT + "#include <${FILE}>\n") endforeach() - set(CMAKE_CONFIGURABLE_FILE_CONTENT - "${CMAKE_CONFIGURABLE_FILE_CONTENT}\nint main(int argc, char** argv)\n{\n (void)argv;\n#ifndef ${SYMBOL}\n return ((int*)(&${SYMBOL}))[argc];\n#else\n (void)argc;\n return 0;\n#endif\n}\n") + string(APPEND CMAKE_CONFIGURABLE_FILE_CONTENT + "\nint main(int argc, char** argv)\n{\n (void)argv;\n#ifndef ${SYMBOL}\n return ((int*)(&${SYMBOL}))[argc];\n#else\n (void)argc;\n return 0;\n#endif\n}\n") configure_file("${CMAKE_ROOT}/Modules/CMakeConfigurableFile.in" - "${SOURCEFILE}" @ONLY IMMEDIATE) + "${SOURCEFILE}" @ONLY) - message(STATUS "Looking for ${SYMBOL}") + if(NOT CMAKE_REQUIRED_QUIET) + message(STATUS "Looking for ${SYMBOL}") + endif() try_compile(${VARIABLE} ${CMAKE_BINARY_DIR} "${SOURCEFILE}" @@ -78,7 +92,9 @@ macro(_CHECK_SYMBOL_EXISTS SOURCEFILE SYMBOL FILES VARIABLE) "${CMAKE_SYMBOL_EXISTS_INCLUDES}" OUTPUT_VARIABLE OUTPUT) if(${VARIABLE}) - message(STATUS "Looking for ${SYMBOL} - found") + if(NOT CMAKE_REQUIRED_QUIET) + message(STATUS "Looking for ${SYMBOL} - found") + endif() set(${VARIABLE} 1 CACHE INTERNAL "Have symbol ${SYMBOL}") file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log "Determining if the ${SYMBOL} " @@ -86,7 +102,9 @@ macro(_CHECK_SYMBOL_EXISTS SOURCEFILE SYMBOL FILES VARIABLE) "${OUTPUT}\nFile ${SOURCEFILE}:\n" "${CMAKE_CONFIGURABLE_FILE_CONTENT}\n") else() - message(STATUS "Looking for ${SYMBOL} - not found") + if(NOT CMAKE_REQUIRED_QUIET) + message(STATUS "Looking for ${SYMBOL} - not found") + endif() set(${VARIABLE} "" CACHE INTERNAL "Have symbol ${SYMBOL}") file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log "Determining if the ${SYMBOL} " |