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If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] .TH fseek 3C "1 Nov 2003" "SunOS 5.11" "Standard C Library Functions" .SH NAME fseek, fseeko \- reposition a file-position indicator in a stream .SH SYNOPSIS .LP .nf #include \fBint\fR \fBfseek\fR(\fBFILE *\fR\fIstream\fR, \fBlong\fR \fIoffset\fR, \fBint\fR \fIwhence\fR); .fi .LP .nf \fBint\fR \fBfseeko\fR(\fBFILE *\fR\fIstream\fR, \fBoff_t\fR \fIoffset\fR, \fBint\fR \fIwhence\fR); .fi .SH DESCRIPTION .sp .LP The \fBfseek()\fR function sets the file-position indicator for the stream pointed to by \fIstream\fR. The \fBfseeko()\fR function is identical to \fBfseek()\fR except for the type of \fIoffset\fR. .sp .LP The new position, measured in bytes from the beginning of the file, is obtained by adding \fIoffset\fR to the position specified by \fIwhence\fR, whose values are defined in <\fBstdio.h\fR> as follows: .sp .ne 2 .mk .na \fB\fBSEEK_SET\fR\fR .ad .RS 12n .rt Set position equal to \fIoffset\fR bytes. .RE .sp .ne 2 .mk .na \fB\fBSEEK_CUR\fR\fR .ad .RS 12n .rt Set position to current location plus \fIoffset\fR. .RE .sp .ne 2 .mk .na \fB\fBSEEK_END\fR\fR .ad .RS 12n .rt Set position to \fBEOF\fR plus \fIoffset\fR. .RE .sp .LP If the stream is to be used with wide character input/output functions, \fIoffset\fR must either be 0 or a value returned by an earlier call to \fBftell\fR(3C) on the same stream and \fIwhence\fR must be \fBSEEK_SET\fR. .sp .LP A successful call to \fBfseek()\fR clears the end-of-file indicator for the stream and undoes any effects of \fBungetc\fR(3C) and \fBungetwc\fR(3C) on the same stream. After an \fBfseek()\fR call, the next operation on an update stream may be either input or output. .sp .LP If the most recent operation, other than \fBftell\fR(3C), on a given stream is \fBfflush\fR(3C), the file offset in the underlying open file description will be adjusted to reflect the location specified by \fBfseek()\fR. .sp .LP The \fBfseek()\fR function allows the file-position indicator to be set beyond the end of existing data in the file. If data is later written at this point, subsequent reads of data in the gap will return bytes with the value 0 until data is actually written into the gap. .sp .LP The value of the file offset returned by \fBfseek()\fR on devices which are incapable of seeking is undefined. .sp .LP If the stream is writable and buffered data had not been written to the underlying file, \fBfseek()\fR will cause the unwritten data to be written to the file and mark the \fBst_ctime\fR and \fBst_mtime\fR fields of the file for update. .SH RETURN VALUES .sp .LP The \fBfseek()\fR and \fBfseeko()\fR functions return \fB0\fR on success; otherwise, they returned \fB\(mi1\fR and set \fBerrno\fR to indicate the error. .SH ERRORS .sp .LP The \fBfseek()\fR and \fBfseeko()\fR functions will fail if, either the \fIstream\fR is unbuffered or the \fIstream\fR's buffer needed to be flushed, and the call to \fBfseek()\fR or \fBfseeko()\fR causes an underlying \fBlseek\fR(2) or \fBwrite\fR(2) to be invoked: .sp .ne 2 .mk .na \fB\fBEAGAIN\fR\fR .ad .RS 10n .rt The \fBO_NONBLOCK\fR flag is set for the file descriptor and the process would be delayed in the write operation. .RE .sp .ne 2 .mk .na \fB\fBEBADF\fR\fR .ad .RS 10n .rt The file descriptor underlying the stream file is not open for writing or the stream's buffer needed to be flushed and the file is not open. .RE .sp .ne 2 .mk .na \fB\fBEFBIG\fR\fR .ad .RS 10n .rt An attempt was made to write a file that exceeds the maximum file size or the process's file size limit, or the file is a regular file and an attempt was made to write at or beyond the offset maximum associated with the corresponding stream. .RE .sp .ne 2 .mk .na \fB\fBEINTR\fR\fR .ad .RS 10n .rt The write operation was terminated due to the receipt of a signal, and no data was transferred. .RE .sp .ne 2 .mk .na \fB\fBEINVAL\fR\fR .ad .RS 10n .rt The \fIwhence\fR argument is invalid. The resulting file-position indicator would be set to a negative value. .RE .sp .ne 2 .mk .na \fB\fBEIO\fR\fR .ad .RS 10n .rt A physical I/O error has occurred; or the process is a member of a background process group attempting to perform a \fBwrite\fR(2) operation to its controlling terminal, \fBTOSTOP\fR is set, the process is neither ignoring nor blocking \fBSIGTTOU\fR, and the process group of the process is orphaned. .RE .sp .ne 2 .mk .na \fB\fBENOSPC\fR\fR .ad .RS 10n .rt There was no free space remaining on the device containing the file. .RE .sp .ne 2 .mk .na \fB\fBENXIO\fR\fR .ad .RS 10n .rt A request was made of a non-existent device, or the request was outside the capabilities of the device. .RE .sp .ne 2 .mk .na \fB\fBEPIPE\fR\fR .ad .RS 10n .rt The file descriptor underlying \fIstream\fR is associated with a pipe or FIFO. .RE .sp .ne 2 .mk .na \fB\fBEPIPE\fR\fR .ad .RS 10n .rt An attempt was made to write to a pipe or \fBFIFO\fR that is not open for reading by any process. A \fBSIGPIPE\fR signal will also be sent to the calling thread. .RE .sp .LP The \fBfseek()\fR function will fail if: .sp .ne 2 .mk .na \fB\fBEOVERFLOW\fR\fR .ad .RS 13n .rt The resulting file offset would be a value which cannot be represented correctly in an object of type \fBlong\fR. .RE .sp .LP The \fBfseeko()\fR function will fail if: .sp .ne 2 .mk .na \fB\fBEOVERFLOW\fR\fR .ad .RS 13n .rt The resulting file offset would be a value which cannot be represented correctly in an object of type \fBoff_t\fR. .RE .SH USAGE .sp .LP Although on the UNIX system an offset returned by \fBftell()\fR or \fBftello()\fR (see \fBftell\fR(3C)) is measured in bytes, and it is permissible to seek to positions relative to that offset, portability to non-UNIX systems requires that an offset be used by \fBfseek()\fR directly. Arithmetic may not meaningfully be performed on such an offset, which is not necessarily measured in bytes. .sp .LP The \fBfseeko()\fR function has a transitional interface for 64-bit file offsets. See \fBlf64\fR(5). .SH ATTRIBUTES .sp .LP See \fBattributes\fR(5) for descriptions of the following attributes: .sp .sp .TS tab() box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) . ATTRIBUTE TYPEATTRIBUTE VALUE _ Interface StabilityStandard _ MT-LevelMT-Safe .TE .SH SEE ALSO .sp .LP \fBgetrlimit\fR(2), \fBulimit\fR(2), \fBfopen\fR(3UCB), \fBftell\fR(3C), \fBrewind\fR(3C), \fBungetc\fR(3C), \fBungetwc\fR(3C), \fBattributes\fR(5), \fBlf64\fR(5), \fBstandards\fR(5)