c - 在 C 中初始化结构数组

Question

我有以下结构

typedef struct {
    int buf[BUF_SIZE]; // the buffer
    size_t len; // number of items in the buffer
    pthread_mutex_t mutex; // needed to add/remove data from the buffer
    pthread_cond_t can_produce; // signaled when items are removed
    pthread_cond_t can_consume; // signaled when items are added
};

最初我只是简单地初始化如下

buffer_t buffer = {
    .len = 0,
    .mutex = PTHREAD_MUTEX_INITIALIZER,
    .can_produce = PTHREAD_COND_INITIALIZER,
    .can_consume = PTHREAD_COND_INITIALIZER
};

虽然我想用这些值初始化一个 buffer_t 数组，但我不太确定如何正确地执行它。

有点像

buffer_t buffer[NUM_ARRAY] = {
    .len = 0,
    .mutex = PTHREAD_MUTEX_INITIALIZER,
    .can_produce = PTHREAD_COND_INITIALIZER,
    .can_consume = PTHREAD_COND_INITIALIZER
};

(我意识到这是不正确的)

编辑:我最终使用了

buffer_t buffers[NUM_THREADS];

for (i = 0, i < 3, i ++) {
       buffers[i] = (buffer_t) {
                .len = 0,
                .mutex = PTHREAD_MUTEX_INITIALIZER,
                .can_produce = PTHREAD_COND_INITIALIZER,
                .can_consume = PTHREAD_COND_INITIALIZER
            };  
}

Answer 1

如果 NUM_ARRAY 不是太大，您可以这样做:

#define NUM_ARRAY 3

buffer_t buffer[NUM_ARRAY] = {
    { {0}, 0, PTHREAD_MUTEX_INITIALIZER, PTHREAD_COND_INITIALIZER, PTHREAD_COND_INITIALIZER},
    { {0}, 0, PTHREAD_MUTEX_INITIALIZER, PTHREAD_COND_INITIALIZER, PTHREAD_COND_INITIALIZER},
    { {0}, 0, PTHREAD_MUTEX_INITIALIZER, PTHREAD_COND_INITIALIZER, PTHREAD_COND_INITIALIZER}
};

或者您可以像这样显式编码:

buffer_t buffer[NUM_ARRAY];
int i;
for (i=0; i<NUM_ARRAY; i++) {
    memset(buffer[i].buf, 0, sizeof(buffer[i].buf));
    buffer[i].len = 0;
    buffer[i].mutex = PTHREAD_MUTEX_INITIALIZER;
    buffer[i].can_produce = PTHREAD_COND_INITIALIZER;
    buffer[i].can_consume = PTHREAD_COND_INITIALIZER;
}

编辑:

所以看起来 PTHREAD_MUTEX_INITIALIZER 和 PTHREAD_COND_INITIALIZER 宏不能用在这样的赋值中，因为它只能用于初始化并且包含 { 和 } 个字符。

所以你需要像其他人建议的那样使用初始化语法:

buffer_t buffer[NUM_ARRAY];
int i;
for (i=0; i<NUM_ARRAY; i++) {
    buffer[i] = (buffer_t) {
        0, 0, PTHREAD_MUTEX_INITIALIZER, PTHREAD_COND_INITIALIZER, PTHREAD_COND_INITIALIZER
    };
}