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我想为使用python的文件预先分配存储空间。随着的fcntl,我可以℃下在预先分配存储:适用于Python下fcntl的fstore格式
int fd = myFileHandle;
fstore_t store = {F_ALLOCATECONTIG, F_PEOFPOSMODE, 0, aLength};
int ret = fcntl(fd, F_PREALLOCATE, &store);
if(-1 == ret){
store.fst_flags = F_ALLOCATEALL;
ret = fcntl(fd, F_PREALLOCATE, &store);
if (-1 == ret)
return false;
当我试图执行的Python下类似的东西,我得到一个错误22:
F_ALLOCATECONTIG = 2
F_PEOFPOSMODE = 3
F_PREALLOCATE = 42
f = open(source, 'r')
f.seek(0, os.SEEK_END)
size = f.tell()
f.seek(0, os.SEEK_SET)
my_fstore = struct.pack('lllll', F_ALLOCATECONTIG, F_PEOFPOSMODE, 0, size, 0)
d = open(destination, 'w')
fcntl.fcntl(d.fileno(), F_PREALLOCATE, my_fstore)
我传递一个结构调用my_fstore这应该是与执行F_PREALLOCATE时fcntl调用所需的c结构相同。
/* fstore_t type used by F_DEALLOCATE and F_PREALLOCATE commands */
typedef struct fstore {
unsigned int fst_flags; /* IN: flags word */
int fst_posmode; /* IN: indicates use of offset field */
off_t fst_offset; /* IN: start of the region */
off_t fst_length; /* IN: size of the region */
off_t fst_bytesalloc; /* OUT: number of bytes allocated */
} fstore_t;
结构中的所有元素应该是64位长度,因此在python结构中的'l'格式化程序。任何关于我可以做不同的建议?