posix_openpt.3c (2010 09)

posix_openpt(3C) posix_openpt(3C)

NAME

posix_openpt( ) - open a pseudo-terminal master device

SYNOPSIS

#include <stdlib.h>

#include <fcntl.h>

int posix_openpt(int oflag);

Parameters

oflag indicates the ﬁle status ﬂags and ﬁle access modes of the open ﬁle description. Values for oﬂag

are constructed by a bitwise-inclusive OR of ﬂags from the following list, deﬁned in

<fcntl.h>:

O_RDWR Open for reading and writing.

O_NOCTTY

If set posix_openpt()

will not cause the terminal device to become the control-

ling terminal for the process.

DESCRIPTION

The

posix_openpt() function establishes a connection between a master device for a pseudo-terminal

and a ﬁle descriptor. This ﬁle descriptor can be used to refer that device. The ﬁle status ﬂags and ﬁle

access modes of the opened ﬁle descriptor will be set according to the value of oﬂag.

RETURN VALUE

Upon successful completion

posix_openpt()

opens a master pseudo-terminal device and returns a

non-negative integer representing the lowest numbered unused ﬁle descriptor. Otherwise,

posix_openpt() returns -1 and

errno is set to indicate the error.

ERRORS

On failure

posix_openpt() sets one of the following values for

errno:

[EMFILE] OPEN_MAX ﬁle descriptors are currently open in the calling process.

[ENFILE] The maximum allowable number of ﬁles are currently open on the system.

[EINVAL] The value of oﬂag is not valid.

[EAGAIN] Out of pseudo-terminal resources.

[ENOSR] Out of STREAMS resources.

AUTHOR

posix_openpt() was developed by HP.