.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved .TH "FREOPEN" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual" .\" freopen .SH NAME freopen \- open a stream .SH SYNOPSIS .LP \fB#include .br .sp FILE *freopen(const char *restrict\fP \fIfilename\fP\fB, const char *restrict\fP \fImode\fP\fB, .br \ \ \ \ \ \ FILE *restrict\fP \fIstream\fP\fB); .br \fP .SH DESCRIPTION .LP The \fIfreopen\fP() function shall first attempt to flush the stream and close any file descriptor associated with \fIstream\fP. Failure to flush or close the file descriptor successfully shall be ignored. The error and end-of-file indicators for the stream shall be cleared. .LP The \fIfreopen\fP() function shall open the file whose pathname is the string pointed to by \fIfilename\fP and associate the stream pointed to by \fIstream\fP with it. The \fImode\fP argument shall be used just as in \fIfopen\fP(). .LP The original stream shall be closed regardless of whether the subsequent open succeeds. .LP If \fIfilename\fP is a null pointer, the \fIfreopen\fP() function shall attempt to change the mode of the stream to that specified by \fImode\fP, as if the name of the file currently associated with the stream had been used. It is implementation-defined which changes of mode are permitted (if any), and under what circumstances. .LP After a successful call to the \fIfreopen\fP() function, the orientation of the stream shall be cleared, \ the encoding rule shall be cleared, and the associated \fBmbstate_t\fP object shall be set to describe an initial conversion state. .LP The largest value that can be represented correctly in an object of type \fBoff_t\fP shall be established as the offset maximum in the open file description. .SH RETURN VALUE .LP Upon successful completion, \fIfreopen\fP() shall return the value of \fIstream\fP. Otherwise, a null pointer shall be returned, \ and \fIerrno\fP shall be set to indicate the error. .SH ERRORS .LP The \fIfreopen\fP() function shall fail if: .TP 7 .B EACCES Search permission is denied on a component of the path prefix, or the file exists and the permissions specified by \fImode\fP are denied, or the file does not exist and write permission is denied for the parent directory of the file to be created. .TP 7 .B EINTR A signal was caught during \fIfreopen\fP(). .TP 7 .B EISDIR The named file is a directory and \fImode\fP requires write access. .TP 7 .B ELOOP A loop exists in symbolic links encountered during resolution of the \fIpath\fP argument. .TP 7 .B EMFILE {OPEN_MAX} file descriptors are currently open in the calling process. .TP 7 .B ENAMETOOLONG .sp The length of the \fIfilename\fP argument exceeds {PATH_MAX} or a pathname component is longer than {NAME_MAX}. .TP 7 .B ENFILE The maximum allowable number of files is currently open in the system. .TP 7 .B ENOENT A component of \fIfilename\fP does not name an existing file or \fIfilename\fP is an empty string. .TP 7 .B ENOSPC The directory or file system that would contain the new file cannot be expanded, the file does not exist, and it was to be created. .TP 7 .B ENOTDIR A component of the path prefix is not a directory. .TP 7 .B ENXIO The named file is a character special or block special file, and the device associated with this special file does not exist. .TP 7 .B EOVERFLOW The named file is a regular file and the size of the file cannot be represented correctly in an object of type \fBoff_t\fP. .TP 7 .B EROFS The named file resides on a read-only file system and \fImode\fP requires write access. .sp .LP The \fIfreopen\fP() function may fail if: .TP 7 .B EINVAL The value of the \fImode\fP argument is not valid. .TP 7 .B ELOOP More than {SYMLOOP_MAX} symbolic links were encountered during resolution of the \fIpath\fP argument. .TP 7 .B ENAMETOOLONG .sp Pathname resolution of a symbolic link produced an intermediate result whose length exceeds {PATH_MAX}. .TP 7 .B ENOMEM Insufficient storage space is available. .TP 7 .B ENXIO A request was made of a nonexistent device, or the request was outside the capabilities of the device. .TP 7 .B ETXTBSY The file is a pure procedure (shared text) file that is being executed and \fImode\fP requires write access. .sp .LP \fIThe following sections are informative.\fP .SH EXAMPLES .SS Directing Standard Output to a File .LP The following example logs all standard output to the \fB/tmp/logfile\fP file. .sp .RS .nf \fB#include \&... FILE *fp; \&... fp = freopen ("/tmp/logfile", "a+", stdout); \&... \fP .fi .RE .SH APPLICATION USAGE .LP The \fIfreopen\fP() function is typically used to attach the preopened \fIstreams\fP associated with \fIstdin\fP, \fIstdout\fP, and \fIstderr\fP to other files. .SH RATIONALE .LP None. .SH FUTURE DIRECTIONS .LP None. .SH SEE ALSO .LP \fIfclose\fP() , \fIfopen\fP() , \fIfdopen\fP() , \fImbsinit\fP() , the Base Definitions volume of IEEE\ Std\ 1003.1-2001, \fI\fP .SH COPYRIGHT Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .