请教一个在pthread线程函数中使用回调函数的问题

[toongyu_zty]

以下就是想在线程函数中使用回调函数的代码，编译通过，运行结果正常。不过，在使用gcc编译时会提示：
warning: passing argument 3 of 'pthread_create' from incompatible pointer type [-Wincompatible-pointer-types]
expected 'void * (*)(void *)' but argument is of type 'void * (*)(void (*)())'
我想知道代码怎么改能去掉这个提示，望大伙赐教。

#include <stdio.h>
#include <unistd.h>
#include <pthread.h>

//回调函数
void OutputSth(const char *str)
{
    printf("%s\n", str);
}

//线程函数
void *ThreadRun(void (*func)())
{
    const char str[20] = "hello callback.";
    int i = 0;
    for(; i < 10; ++i)
    {
        func(str);
        sleep(1);
    }

    return NULL;
}

int main(void)
{
    pthread_t thd;
    pthread_create(&thd, NULL, ThreadRun, OutputSth);
    pthread_join(thd, NULL);

    return 0;
}

[paschen]

void *ThreadRun(void (*func)()) 这个函数的参数类型应该是void* 也就是说是：void *ThreadRun(void * func) 这样的形式

[自信男孩]

pthread_create第三个参数是void *类型，但是void (*func)()函数的返回值是void类型，与void *冲突。 下面的修改，参考一下吧

#include <stdio.h>
#include <unistd.h>
#include <pthread.h>

struct param {
    void (*func)(const char *);
};

//回调函数
void OutputSth(const char *str)
{
    printf("%s\n", str);

    //return NULL;
}

//线程函数
void *ThreadRun(void *arg)
{
    const char str[20] = "hello callback.";
    struct param *p = (struct param *)arg;
    int i = 0;
    for(; i < 10; ++i)
    {
        p->func(str);
        sleep(1);
    }

    return NULL;
}

int main(void)
{
    pthread_t thd;
    struct param arg;
    arg.func = OutputSth;
    pthread_create(&thd, NULL, ThreadRun, (void *)&arg);
    pthread_join(thd, NULL);

    return 0;
}

[toongyu_zty]

引用 2 楼 cfjtaishan 的回复:

pthread_create第三个参数是void *类型，但是void (*func)()函数的返回值是void类型，与void *冲突。 下面的修改，参考一下吧

#include <stdio.h>
#include <unistd.h>
#include <pthread.h>

struct param {
    void (*func)(const char *);
};

//回调函数
void OutputSth(const char *str)
{
    printf("%s\n", str);

    //return NULL;
}

//线程函数
void *ThreadRun(void *arg)
{
    const char str[20] = "hello callback.";
    struct param *p = (struct param *)arg;
    int i = 0;
    for(; i < 10; ++i)
    {
        p->func(str);
        sleep(1);
    }

    return NULL;
}

int main(void)
{
    pthread_t thd;
    struct param arg;
    arg.func = OutputSth;
    pthread_create(&thd, NULL, ThreadRun, (void *)&arg);
    pthread_join(thd, NULL);

    return 0;
}

十分感谢，学习了

[乞丐的生鱼片]

线程对应的函数的格式必须是这样：void *xxoo(void *arg) a.把“void *sayhello(void *arg)”改成“void sayhello(void *arg)”会报错如下： root@book-desktop:/opt/pc_test/multithreading/1# make gcc -o main main.c -lpthread main.c: In function ‘main’: main.c:14: warning: passing argument 3 of ‘pthread_create’ from incompatible pointer type /usr/include/pthread.h:227: note: expected ‘void * (*)(void *)’ but argument is of type ‘void (*)(void *)’ b.把“void *sayhello(void *arg)”改成“void *sayhello(void)”会报错如下： root@book-desktop:/opt/pc_test/multithreading/1# make gcc -o main main.c -lpthread main.c: In function ‘main’: main.c:14: warning: passing argument 3 of ‘pthread_create’ from incompatible pointer type /usr/include/pthread.h:227: note: expected ‘void * (*)(void *)’ but argument is of type ‘void * (*)(void)’