set(NUMBERS "") set(COUNT 0) while(COUNT LESS 200) string(APPEND NUMBERS " ${COUNT}") set(COUNT "2${COUNT}") set(NCOUNT 3) while(NCOUNT LESS 31) string(APPEND NUMBERS " ${NCOUNT}") string(APPEND NCOUNT "0") endwhile() endwhile() if(NOT NUMBERS STREQUAL " 0 3 30 20 3 30") message(SEND_ERROR "while loop nesting error, result: '${NUMBERS}'") endif()