gno/usr.man/man3/fgets.3

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.\"     @(#)fgets.3	8.1 (Berkeley) 6/4/93
.\"
.TH FGETS 3 "15 September 1997" GNO "Library Routines"
.SH NAME
.BR fgets ,
.BR gets
\- get a line from a stream
.SH SYNOPSIS
#include <stdio.h>
.sp 1
char *\fBfgets\fR (char *\fIstr\fR, size_t \fIsize\fR, FILE *\fIstream\fR);
.br
char *\fBgets\fR (char *\fIstr\fR);
.SH DESCRIPTION
The
.BR fgets 
function
reads at most one less than the number of characters specified by
.I size
from the given
.I stream
and stores them in the string
.IR str .
Reading stops when a newline character is found,
at end-of-file or error.
The newline, if any, is retained.
If any characters are read and there is no error, a
.BR \e0
character is appended to end the string.
.LP
The
.BR gets 
function
is equivalent to
.BR fgets 
with an infinite
.I size
and a
.I stream
of
.IR stdin ,
except that the newline character (if any) is not stored in the string.
It is the caller's responsibility to ensure that the input line,
if any, is sufficiently short to fit in the string.
.SH RETURN VALUES
.LP
Upon successful completion,
.BR fgets 
and 
.BR gets 
return
a pointer to the string.
If end-of-file occurs before any characters are read, 
they return
.BR NULL
and the buffer contents is unchanged.
If an error occurs,
they return
.BR NULL
and the buffer contents is indeterminate.
The
.BR fgets 
and
.BR gets 
functions
do not distinguish between end-of-file and error, and callers must use
.BR feof (3)
and
.BR ferror (3)
to determine which occurred.
.SH ERRORS
.RS
.IP \fBEBADF\fR
The given
.I stream
is not a readable stream.
.RE
.LP
The function
.BR fgets 
may also fail and set
.IR errno
for any of the errors specified for the routines
.BR fflush (3),
.BR fstat (2),
.BR read (2),
or
.BR malloc (3).
.LP
The function
.BR gets 
may also fail and set
.IR errno
for any of the errors specified for the routine
.BR getchar (3).
.SH GNO NOTES
If these routines are used on a stream which has been opened in binary
mode, the results may not be as is expected; this stdio implementation
has the assumption that the newline character is the linefeed (\\n).
Since a file opened in binary mode will usually, on the IIgs, use
carridge returns as the newline characters, the 
.BR fgets
and 
.BR gets 
routines will return more characters than expected.  
.I "This makes use of"
.B gets
.IR "particularly dangerous under GNO"
(see the section on BUGS, below).
.SH SEE ALSO
.BR feof (3),
.BR ferror (3),
.BR fgetln (3)
.SH STANDARDS
The functions
.BR fgets 
and
.BR gets 
conform to ANSI/C.
.SH BUGS
Since it is usually impossible to ensure that the next input line
is less than some arbitrary length, and because overflowing the
input buffer is almost invariably a security violation, programs
should
.IR NEVER 
use
.BR gets .
The
.BR gets 
function
exists purely to conform to ANSI/C.