.TH subfd 3
.SH NAME
subfd \- standard input, output, error for substdio
.SH SYNTAX
.B #include <subfd.h>

substdio *\fBsubfdin\fP;
.br
substdio *\fBsubfdout\fP;
.br
substdio *\fBsubfderr\fP;

int \fBsubfd_read\fP(\fIfd\fR,\fIbuf\fR,\fIlen\fR);

substdio *\fBsubfdinsmall\fP;
.br
substdio *\fBsubfdoutsmall\fP;

int \fBsubfd_readsmall\fP(\fIfd\fR,\fIbuf\fR,\fIlen\fR);

int \fIfd\fR;
.br
char *\fIbuf\fR;
.br
int \fIlen\fR;
.SH DESCRIPTION
.B subfderr
writes data to descriptor 2.

.B subfdout
writes data to descriptor 1.

.B subfdin
reads data from descriptor 0.
It coordinates with
.BR subfdout :
it flushes
.B subfdout
before refilling its buffer.
This eliminates the need for
.B subfdout
flushing in most programs.
To set up the same flushing mechanism for another input descriptor,
use
.B subfd_read
in place of
.BR read .

.BR subfdoutsmall ,
.BR subfd_readsmall ,
and
.B subfdinsmall
behave the same way as
.BR subfdout ,
.BR subfd_read ,
and
.BR subfdin ,
except that they use small (256-byte) buffers.
This is appropriate for programs that read data in small chunks.
.SH "SEE ALSO"
substdio(3)