mmap errno 22 in c read openmpi数据类型解密

Question

我正在使用mmap来读取文件。mmap返回错误号errno 22。在这种情况下，stat.st_size为400，我认为它不是“太大”。我认为我不会遇到“我们不喜欢addr，length或offset”。我正在Intel Xeon E5上运行此程序（我认为它不相关）。我在这里想念什么？

if( argc > 1 ) {
    struct stat stat;

    for( int i = 1; i < argc; i++ ) {
        if( access(argv[i], R_OK) == -1 ) {
            printf("\n Cannot access datatype description file %s\n", argv[i]);
            continue;
        }
        int fd = open(argv[i], O_RDONLY);
        if( fd == -1 ) {
            printf("\n Cannot open datatype description from file %s\n", argv[i]);
            continue;
        }
        if( fstat(fd, &stat) == -1 ) {
            printf("\n Cannot stat the %s file\n", argv[i]);
            continue;
        }

        void* addr = mmap(NULL, stat.st_size, PROT_READ, MAP_FILE, fd, 0);

        if( MAP_FAILED == addr ) {
            printf("\nCannot map the datatype description file %s\n", argv[i]);
            printf("%s %d stat.st_size %d\n", strerror(errno), errno, stat.st_size );
            perror("mmap");
            close(fd);
            continue;
        }

        munmap(addr, stat.st_size);
        free(addr);
        close(fd);
    }
}

Answer 1

来自man 2 mmap：

       MAP_FILE
              Compatibility flag.  Ignored.
...
       EINVAL flags  contained neither MAP_PRIVATE or MAP_SHARED, or contained
              both of these values.

您需要传递MAP_PRIVATE或MAP_SHARED之一，并且您应停止传递MAP_FILE。 （您甚至认为它做了什么？）