include(CheckTypeSize) check_type_size("long int" SIZEOF_LONG_INT) check_type_size("long long" SIZEOF_LONG_LONG) check_type_size("void *" SIZEOF_VOID_P) # checks existence of ${_type}, and if it does not, sets CMake variable ${_var} # to alternative type, ${_alt_type} macro(CheckType _type _alt_type _var) check_type_size(${_type} ${_var}) if (NOT ${_var}) set(${_var} ${_alt_type}) else () unset(${_var}) unset(${_var} CACHE) endif () endmacro(CheckType _type _alt_type _var) set(CMAKE_EXTRA_INCLUDE_FILES sys/types.h) CheckType(int32_t int int32_t) CheckType(u_int32_t u_int u_int32_t) CheckType(u_int16_t u_short u_int16_t) CheckType(u_int8_t u_char u_int8_t) set(CMAKE_EXTRA_INCLUDE_FILES) set(CMAKE_EXTRA_INCLUDE_FILES sys/socket.h) CheckType(socklen_t int socklen_t) set(CMAKE_EXTRA_INCLUDE_FILES)