回调函数

-6

// issue with the following not returning info or just stalling... but no errors 
static int callback(void *voidParam, int argc, char **argv, char **azColName) 
{ 
    static int k = 0; 
    myReturn structReturn; 

    char *cTempF = (argv[0] ? argv[0] : "NULL"); 
    memcpy(&structReturn.cFirstName, cTempF, sizeof(cTempF));// tried strlen(cTempF)... no help 

    memcpy(voidParam + k * sizeof(structReturn), &structReturn, sizeof(structReturn)); 

    k++; 
}

myReturn *structReturn = (myReturn*)malloc(sizeof(myReturn) * 20); 

rc = sqlite3_exec(db, pSQL, callback, structReturn, &zErrMsg);

typedef struct ReturnTag 
{ 
    char cFirstName[100]; 
    char cLastName[100]; 
    short int iAge; 
}myReturn;

来源

2012-06-29 jdl

什么是您所遇到的问题是什么？请更准确地描述问题。 –

我想我在评论中描述得非常好......当我执行“memcpy（＆structReturn.cLastName，cTempL，strlen（cTempL））时，没有返回任何东西;”为“char * cTempF =（argv [0]？argv [0]：”NULL“）;”但返回“char cTempF [] =”狗“;” – jdl

你是什么意思“没有回报”？你是说'memcpy'不会将内存内容从'cTempF'复制到'structReturn.cFirstName'？ –

解决它...需要：memset(&structReturn.cFirstName, '\0', 100);

static int callback(void *voidParam, int argc, char **argv, char **azColName) 
{ 
    static int k = 0; 
    myReturn structReturn; 

    char *cTempF = (argv[0] ? argv[0] : "NULL"); 
    memset(&structReturn.cFirstName, '\0', 100); // <--- needed here 
    memcpy(&structReturn.cFirstName, cTempF, strlen(cTempF)); 

    memcpy(voidParam + k * sizeof(structReturn), &structReturn, sizeof(structReturn)); 

    k++; 
}

来源

2012-06-29 23:17:22 jdl

更有可能您只需要复制0结束符'memcpy（＆structReturn.cFirstName，cTempF，strlen（cTempF）+ 1）'。 –

回答

相关问题