cmake: CHECK_INCLUDE_FILE_CXX 检查是否存在 codecvt 头文件

今天第一次使用cmake的CHECK_INCLUDE_FILE_CXX 函数检查是否存在 codecvt include文件，然而出错了(编译器使用gcc 5.4.0)。 cmake脚本如下：

include(CheckIncludeFileCXX)
# 检查是否存在 codecvt header file
CHECK_INCLUDE_FILE_CXX(codecvt HAS_CODECVT )
# 检查是否存在 algorithm header file
CHECK_INCLUDE_FILE_CXX(algorithm HAS_ALGORITHM )
message(HAS_CODECVT=${HAS_CODECVT})
message(HAS_ALGORITHM=${HAS_ALGORITHM})

输出显示，能找到algorithm,却找不到codecvt

– Looking for C++ include codecvt – Looking for C++ include codecvt - not found – Looking for C++ include algorithm – Looking for C++ include algorithm - found HAS_CODECVT= HAS_ALGORITHM=1

明明我看到存在这个codecvt文件，cmake输出就是找不到 想来codecvt是在c++11标准下才支持的文件，于是我如下增加-std=c++11 编译选项再试则问题解决

include(CheckIncludeFileCXX)
set(CMAKE_REQUIRED_FLAGS -std=c++11)
# 检查是否存在 codecvt header file
CHECK_INCLUDE_FILE_CXX(codecvt HAS_CODECVT )
# 检查是否存在 algorithm header file
CHECK_INCLUDE_FILE_CXX(algorithm HAS_ALGORITHM )
message(HAS_CODECVT=${HAS_CODECVT})
message(HAS_ALGORITHM=${HAS_ALGORITHM})

– Looking for C++ include codecvt – Looking for C++ include codecvt - found – Looking for C++ include algorithm – Looking for C++ include algorithm - found HAS_CODECVT=1 HAS_ALGORITHM=1