C:如何从文件中读取一个jpg并保存？

Question

我在读取和保存 jpg 文件时遇到了一些问题。我想在客户端和服务器之间实现一个文件共享系统，我什至无法读取 jpg 并将其保存在同一进程中。这是我目前所拥有的

int main(int argc, const char * argv[])
{
    char *buffer;
    FILE *picture;
    FILE *newPicture;
    struct stat st;
    long fileSize = 0;


    picture = fopen("PATH/root/game-of-thrones-poster.jpg", "rb");
    fstat(picture, &st);
    fileSize = st.st_size;
    if(fileSize > 0) {
        buffer = malloc(fileSize);

        if(read(picture, buffer, fileSize) < 0) {
            printf("Error reading file");
        }
        fclose(picture);

        newPicture = fopen("PATH/root/new.jpg", "wb");
        write(newPicture, buffer, fileSize);
    }
    free(buffer);
}

当它尝试读取文件时，它告诉我文件大小为 0。

Answer 1

fstat() is identical to stat(), except that the file to be stat-ed is specified by the file descriptor fd.

您正在传递 FILE *，fstat 需要一个 int