QIO(3)QIO(3)NAMEqio - quick I/O part of InterNetNews library
SYNOPSIS
#include "qio.h"
QIOSTATE *
QIOopen(name, size)
char *name;
int size;
QIOSTATE *
QIOfdopen(fd, size)
int fd;
int size;
void
QIOclose(qp)
QIOSTATE *qp;
char *
QIOread(qp)
QIOSTATE *qp;
int
QIOlength(qp)
QIOSTATE *qp;
int
QIOtoolong(qp)
QIOSTATE *qp;
int
QIOerror(qp)
QIOSTATE *qp;
int
QIOtell(qp)
QIOSTATE *qp;
int
QIOrewind(qp)
QIOSTATE *qp;
int
QIOfileno(qp)
QIOSTATE *qp;
DESCRIPTION
The routines described in this manual page are part of the InterNetNews
library, libinn(3). They are used to provide quick read access to
files. The letters ``QIO'' stand for Quick I/O.
QIOopen opens the file name for reading. It uses a buffer of size
bytes, which must also be larger then the longest expected line. The
header file defines the constant QIO_BUFFER as a reasonable default.
If size is zero, then QIOopen will call stat(2) and use the returned
block size; if that fails it will use QIO_BUFFER. It returns NULL on
error, or a pointer to a handle to be used in other calls. QIOfdopen
performs the same function except that fd refers to an already-open
descriptor.
QIOclose closes the open file and releases any resources used by it.
QIOread returns a pointer to the next line in the file. The trailing
newline will be replaced with a \0. If EOF is reached, an error
occurs, or if the line is longer than the buffer, QIOread returns NULL.
After a successful call to QIOread, QIOlength will return the length of
the current line.
The functions QIOtoolong and QIOerror can be called after QIOread
returns NULL to determine if there was an error, or if the line was too
long. If QIOtoolong returns non-zero, then the current line did not
fit in the buffer, and the next call to QIOread will try read the rest
of the line. Long lines can only be discarded. If QIOerror returns
non-zero, then a serious I/O error occurred.
QIOtell returns the lseek(2) offset at which the next line will start.
QIOrewind sets the read pointer back to the beginning of the file.
QIOfileno returns the descriptor of the open file.
QIOlength, QIOtoolong, QIOerror, QIOtell, and QIOfileno are implemented
as macro's defined in the header file.
EXAMPLE
QIOSTATE *h;
long offset;
char *p;
h = QIOopen("/etc/motd", QIO_BUFFER);
for (offset = QIOtell(h); (p = QIOread(h)) != NULL; offset = QIOtell(h))
printf("At %ld, %s\n", offset, p);
if (QIOerror(h)) {
perror("Read error");
exit(1);
}
QIOclose(h);
HISTORY
Written by Rich $alz <rsalz@uunet.uu.net> for InterNetNews. This is
revision 1.7, dated 1993/01/29.
QIO(3)