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.\"     @(#)fgetline.3	5.4 (Berkeley) 4/19/91
.\"
.TH FGETLINE 3
.DA April 19, 1991
.SH NAME
fgetline \- get a line from a stream
.SH SYNOPSIS
.nf
.ft B
#include <stdio.h>
char *
fgetline(FILE *stream, size_t *len)
.ft
.fi
.SH DESCRIPTION
The
.I fgetline
function
returns a pointer to the next line from the stream referenced by
.IR stream .
The newline character at the end of the line is replaced by a
.IR NUL .
.Pp
If
.I len
is non-NULL, the length of the line, not counting the terminating
.IR NUL ,
is stored in the memory location it references.
.SH RETURN VALUES
Upon successful completion a pointer is returned;
this pointer becomes invalid after the next
.I I/O
operation on
.I stream
(whether successful or not)
or as soon as the stream is closed.
Otherwise,
.I NULL
is returned.
The
.I fgetline
function
does not distinguish between end-of-file and error; the routines
.IR feof (3)
and
.IR ferror (3)
must be used
to determine which occurred.
If an error occurrs, the global variable
.I errno
is set to indicate the error.
The end-of-file condition is remembered, even on a terminal, and all
subsequent attempts to read will return
.I NULL
until the condition is
cleared with
.IR clearerr (3).
.PP
The text to which the returned pointer points may be modified,
provided that no changes are made beyond the terminating
.IR NUL .
These changes are lost as soon as the pointer becomes invalid.
.SH ERRORS
.TP
[EBADF]
The argument
.I stream
is not a stream open for reading.
.PP
The
.I fgetline
function
may also fail and set
.I errno
for any of the errors specified for the routines
.IR fflush (3),
.IR malloc (3),
.IR read (2),
.IR stat (2),
or
.IR realloc (3).
.SH SEE ALSO
.IR ferror (3),
.IR fgets (3),
.IR fopen (3),
.IR putc (3)
.SH HISTORY
The
.I fgetline
function is
new.
.SH BUGS
It is not possible to tell whether the final line of an input file
was terminated with a newline.