Guardian Native C Library Calls Reference Manual (G06.28+, H06.05+)

fseeko(3) Guardian Native C Library Calls Reference Manual
NAME
fseeko - Repositions the file pointer of a stream
LIBRARY
G-series native Guardian processes: $SYSTEM.SYSnn.ZCRTLSRL
G-series native OSS processes: /G/system/sysnn/zcrtlsrl
H-series native Guardian processes: $SYSTEM.ZDLLnnn.ZCRTLDLL
H-series OSS processes: /G/system/zdllnnn/zcrtldll
SYNOPSIS
#include <stdio.h>
int fseeko(
FILE ∗∗stream,
off_t offset,
int whence);
PARAMETERS
stream Specifies the I/O stream.
offset Determines the position of the next operation.
whence Determines the value for the file pointer associated with the stream parameter.
DESCRIPTION
The fseeko() function is identical to the fseek() function except that its return value is of type
off_t.
An application can explicitly call this function when you compile the application using the
#define _LARGEFILE64_SOURCE 1 feature test macro or an equivalent compiler command
option.
The fseeko() function sets the position of the next input or output operation on the I/O stream
specified by the stream parameter. The offset parameter, which can be either positive or negative,
determines the position of the next operation.
The fseeko() function sets the file pointer associated with the specified stream as follows:
• If the whence parameter is SEEK_SET, the pointer is set to the value of the offset
parameter.
• If the whence parameter is SEEK_CUR, the pointer is set to its current location plus the
value of the offset parameter.
• If the whence parameter is SEEK_END, the pointer is set to the size of the file plus the
value of the offset parameter.
The fseeko() function fails if attempted on a file that was not opened with the fopen( ) function.
In particular, you cannot use the fseeko() function on a terminal or on a file opened with the
popen( ) function.
A successful call to the fseeko() function clears the End-of-File indicator for the stream and
undoes any effects of the ungetc() function on the same stream. After a call to the fseeko()
function, the next operation on an update stream can be either input or output.
If the stream is writable, and buffered data was not written to the underlying file, the fseeko()
function causes the unwritten data to be written to the file and marks the st_ctime and st_mtime
fields of the file for update.
If the most recent operation (ignoring any ftell() operations) on a given stream was fflush(), the
fseeko() function causes the file offset in the underlying open file descriptor to be adjusted to
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