получить статус файла (get file status)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
fstat — get file status
Синопсис (Synopsis)
#include <sys/stat.h>
int fstat(int fildes, struct stat *buf);
Описание (Description)
The fstat() function shall obtain information about an open file
associated with the file descriptor fildes, and shall write it to
the area pointed to by buf.
If fildes references a shared memory object, the implementation
shall update in the stat structure pointed to by the buf argument
the st_uid, st_gid, st_size, and st_mode fields, and only the
S_IRUSR, S_IWUSR, S_IRGRP, S_IWGRP, S_IROTH, and S_IWOTH file
permission bits need be valid. The implementation may update
other fields and flags.
If fildes references a typed memory object, the implementation
shall update in the stat structure pointed to by the buf argument
the st_uid, st_gid, st_size, and st_mode fields, and only the
S_IRUSR, S_IWUSR, S_IRGRP, S_IWGRP, S_IROTH, and S_IWOTH file
permission bits need be valid. The implementation may update
other fields and flags.
The buf argument is a pointer to a stat structure, as defined in
<sys/stat.h>, into which information is placed concerning the
file.
For all other file types defined in this volume of POSIX.1‐2017,
the structure members st_mode, st_ino, st_dev, st_uid, st_gid,
st_atim, st_ctim, and st_mtim shall have meaningful values and
the value of the st_nlink member shall be set to the number of
links to the file.
An implementation that provides additional or alternative file
access control mechanisms may, under implementation-defined
conditions, cause fstat() to fail.
The fstat() function shall update any time-related fields (as
described in the Base Definitions volume of POSIX.1‐2017, Section
4.9, File Times Update), before writing into the stat structure.
Возвращаемое значение (Return value)
Upon successful completion, 0 shall be returned. Otherwise, -1
shall be returned and errno set to indicate the error.
Ошибки (Error)
The fstat() function shall fail if:
EBADF The fildes argument is not a valid file descriptor.
EIO An I/O error occurred while reading from the file system.
EOVERFLOW
The file size in bytes or the number of blocks allocated
to the file or the file serial number cannot be
represented correctly in the structure pointed to by buf.
The fstat() function may fail if:
EOVERFLOW
One of the values is too large to store into the structure
pointed to by the buf argument.
The following sections are informative.
Примеры (Examples)
Obtaining File Status Information
The following example shows how to obtain file status information
for a file named /home/cnd/mod1. The structure variable buffer
is defined for the stat structure. The /home/cnd/mod1 file is
opened with read/write privileges and is passed to the open file
descriptor fildes.
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
struct stat buffer;
int status;
...
fildes = open("/home/cnd/mod1", O_RDWR);
status = fstat(fildes, &buffer);
Использование в приложениях (Application usage)
None.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
fstatat(3p)
The Base Definitions volume of POSIX.1‐2017, Section 4.9, File
Times Update, sys_stat.h(0p), sys_types.h(0p)
