所以我只是想编译这个示例 mysql C++ 程序。如果我将 g++ -Wall -I/usr/include/cppconn -o mysql_test mysql_test.cpp -L/usr/lib -lmysqlcppconn
放在命令行上,它将编译并运行得很好。如果我尝试使用 make,它会由于未定义的函数调用而失败。 make 脚本有什么问题?
g++ -o prog mysql_test.o mysql_test.o: In function
main': mysql_test.cpp:(.text+0x3a): undefined reference to
get_driver_instance' collect2: error: ld returned 1 exit status make: *** [all] Error 1
这是生成文件:
CXX=g++
#CXXFLAGS=-g -std=c++0x -Wall -pedantic -lmysqlcppconn -lmysqlcppconn-static
CXXFLAGS=-g -std=c++0x -Wall -I/usr/include/cppconn -L/usr/lib -lmysqlcppconn
BIN=prog
SRC=$(wildcard *.cpp)
OBJ=$(SRC:%.cpp=%.o)
all: $(OBJ)
$(CXX) -o $(BIN) $^
%.o: %.c
$(CXX) $@ -c $<
clean:
rm -f *.o
rm $(BIN)
这是 cpp 源代码:
#include <stdlib.h>
#include <iostream>
/*
Include directly the different
headers from cppconn/ and mysql_driver.h + mysql_util.h
(and mysql_connection.h). This will reduce your build time!
*/
#include <mysql_connection.h>
#include <cppconn/driver.h>
#include <cppconn/exception.h>
#include <cppconn/resultset.h>
#include <cppconn/statement.h>
using namespace std;
int main(void)
{
cout << endl;
cout << "Running 'SELECT 'Hello World!' AS _message'..." << endl;
try {
sql::Driver *driver;
sql::Connection *con;
sql::Statement *stmt;
sql::ResultSet *res;
/* Create a connection */
driver = get_driver_instance();
con = driver->connect("tcp://127.0.0.1:3306", "root", "password");
/* Connect to the MySQL test database */
con->setSchema("mysql");
stmt = con->createStatement();
res = stmt->executeQuery("SELECT 'Hello World!' AS _message");
while (res->next()) {
cout << "\t... MySQL replies: ";
/* Access column data by alias or column name */
cout << res->getString("_message") << endl;
cout << "\t... MySQL says it again: ";
/* Access column fata by numeric offset, 1 is the first column */
cout << res->getString(1) << endl;
}
delete res;
delete stmt;
delete con;
} catch (sql::SQLException &e) {
cout << "# ERR: SQLException in " << __FILE__;
cout << "(" << __FUNCTION__ << ") on line " << __LINE__ << endl;
cout << "# ERR: " << e.what();
cout << " (MySQL error code: " << e.getErrorCode();
cout << ", SQLState: " << e.getSQLState() << " )" << endl;
}
cout << endl;
return EXIT_SUCCESS;
}
感谢您对此的任何帮助。
这是工作品牌:
CXX=g++
#CXXFLAGS=-g -std=c++0x -Wall -pedantic -lmysqlcppconn -lmysqlcppconn-static
CXXFLAGS=-g -std=c++0x -Wall -I/usr/include/cppconn
LDFLAGS=-L/usr/lib -lmysqlcppconn
BIN=prog
SRC=$(wildcard *.cpp)
OBJ=$(SRC:%.cpp=%.o)
all: $(OBJ)
$(CXX) -o $(BIN) $(LDFLAGS) $^
%.o: %.c
$(CXX) $@ -c $<
clean:
rm -f *.o
rm $(BIN)
最佳答案
-L/usr/lib -lmysqlcppconn
需要在 LD_FLAGS
中。
关于c++ - mysql C++ 不会用 make 编译,但如果 g++ 参数放在 cmd 行,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/29877898/