NAME¶
qio - 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.