mirror of https://github.com/mkerrisk/man-pages
131 lines
4.2 KiB
Plaintext
131 lines
4.2 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "FSTAT" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" fstat
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.SH NAME
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fstat \- get file status
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.SH SYNOPSIS
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.LP
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\fB#include <sys/stat.h>
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.br
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.sp
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int fstat(int\fP \fIfildes\fP\fB, struct stat *\fP\fIbuf\fP\fB);
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.br
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\fP
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.SH DESCRIPTION
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.LP
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The \fIfstat\fP() function shall obtain information about an open
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file associated with the file descriptor \fIfildes\fP, and
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shall write it to the area pointed to by \fIbuf\fP.
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.LP
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If \fIfildes\fP references a shared memory object, the implementation
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shall update in the \fBstat\fP structure pointed to by the
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\fIbuf\fP argument only the \fIst_uid\fP, \fIst_gid\fP, \fIst_size\fP,
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and \fIst_mode\fP fields, and only the S_IRUSR,
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S_IWUSR, S_IRGRP, S_IWGRP, S_IROTH, and S_IWOTH file permission bits
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need be valid. The implementation may update other fields and
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flags.
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.LP
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If \fIfildes\fP references a typed memory object, the implementation
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shall update in the \fBstat\fP structure pointed to by the
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\fIbuf\fP argument only the \fIst_uid\fP, \fIst_gid\fP, \fIst_size\fP,
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and \fIst_mode\fP fields, and only the S_IRUSR,
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S_IWUSR, S_IRGRP, S_IWGRP, S_IROTH, and S_IWOTH file permission bits
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need be valid. The implementation may update other fields and
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flags.
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.LP
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The \fIbuf\fP argument is a pointer to a \fBstat\fP structure, as
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defined in \fI<sys/stat.h>\fP, into which information is placed concerning
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the file.
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.LP
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The structure members \fIst_mode\fP, \fIst_ino\fP, \fIst_dev\fP, \fIst_uid\fP,
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\fIst_gid\fP, \fIst_atime\fP,
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\fIst_ctime\fP, and \fIst_mtime\fP shall have meaningful values for
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all other file types defined in this volume of
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IEEE\ Std\ 1003.1-2001. The value of the member \fIst_nlink\fP shall
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be set to the number of links to the file.
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.LP
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An implementation that provides additional or alternative file access
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control mechanisms may, under implementation-defined
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conditions, cause \fIfstat\fP() to fail.
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.LP
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The \fIfstat\fP() function shall update any time-related fields as
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described in the Base Definitions volume of
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IEEE\ Std\ 1003.1-2001, Section 4.7, File Times Update, before writing
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into the \fBstat\fP structure.
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.SH RETURN VALUE
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.LP
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Upon successful completion, 0 shall be returned. Otherwise, -1 shall
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be returned and \fIerrno\fP set to indicate the error.
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.SH ERRORS
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.LP
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The \fIfstat\fP() function shall fail if:
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.TP 7
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.B EBADF
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The \fIfildes\fP argument is not a valid file descriptor.
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.TP 7
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.B EIO
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An I/O error occurred while reading from the file system.
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.TP 7
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.B EOVERFLOW
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The file size in bytes or the number of blocks allocated to the file
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or the file serial number cannot be represented correctly
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in the structure pointed to by \fIbuf\fP.
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.sp
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.LP
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The \fIfstat\fP() function may fail if:
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.TP 7
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.B EOVERFLOW
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One of the values is too large to store into the structure pointed
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to by the \fIbuf\fP argument.
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.sp
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.LP
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\fIThe following sections are informative.\fP
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.SH EXAMPLES
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.SS Obtaining File Status Information
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.LP
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The following example shows how to obtain file status information
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for a file named \fB/home/cnd/mod1\fP. The structure variable
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\fIbuffer\fP is defined for the \fBstat\fP structure. The \fB/home/cnd/mod1\fP
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file is opened with read/write privileges and is
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passed to the open file descriptor \fIfildes\fP.
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.sp
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.RS
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.nf
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\fB#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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.sp
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struct stat buffer;
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int status;
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\&...
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fildes = open("/home/cnd/mod1", O_RDWR);
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status = fstat(fildes, &buffer);
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\fP
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.fi
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.RE
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.SH APPLICATION USAGE
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.LP
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None.
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.SH RATIONALE
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.LP
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None.
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.SH FUTURE DIRECTIONS
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.LP
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None.
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.SH SEE ALSO
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.LP
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\fIlstat\fP() , \fIstat\fP() , the Base Definitions volume of
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IEEE\ Std\ 1003.1-2001, \fI<sys/stat.h>\fP, \fI<sys/types.h>\fP
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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