posix_openpt(3c) [opensolaris man page]
posix_openpt(3C) Standard C Library Functions posix_openpt(3C) NAME
posix_openpt - open a pseudo terminal device SYNOPSIS
#include <stdlib.h> #include <fcntl.h> int posix_openpt(int oflag); DESCRIPTION
The posix_openpt() function establishes a connection between a master device for a pseudo-terminal and a file descriptor. The file descrip- tor is used by other I/O functions that refer to that pseudo-terminal. The file status flags and file access modes of the open file description are set according to the value of oflag. 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() does not cause the terminal device to become the controlling terminal for the process. The behavior of other values for the oflag argument is unspecified. RETURN VALUES
Upon successful completion, the posix_openpt() function opens a master pseudo-terminal device and returns a non-negative integer represent- ing the lowest numbered unused file descriptor. Otherwise, -1 is returned and errno is set to indicate the error. ERRORS
The posix_openpt() function will fail if: EMFILE {OPEN_MAX} file descriptors are currently open in the calling process. ENFILE The maximum allowable number of files is currently open in the system. The posix_openpt() function may fail if: EINVAL The value of oflag is not valid. EAGAIN Out of pseudo-terminal resources. ENOSR Out of STREAMS resources. EXAMPLES
Example 1 Open a pseudo-terminal. The following example opens a pseudo-terminal and returns the name of the slave device and a file descriptor. #include fcntl.h> #include stdio.h> int masterfd, slavefd; char *slavedevice; masterfd = posix_openpt(O_RDWR|O_NOCTTY); if (masterfd == -1 || grantpt (masterfd) == -1 || unlockpt (masterfd) == -1 || (slavedevice = ptsname (masterfd)) == NULL) return -1; printf("slave device is: %s ", slavedevice); slavefd = open(slave, O_RDWR|O_NOCTTY); if (slavefd < 0) return -1; USAGE
This function provieds a method for portably obtaining a file descriptor of a master terminal device for a pseudo-terminal. The grantpt(3C) and ptsname(3C) functions can be used to manipulate mode and ownership permissions and to obtain the name of the slave device, respec- tively. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ SEE ALSO
open(2), grantpt(3C), ptsname(3C), unlockpt(3C), attributes(5), standards(5) SunOS 5.11 1 Dec 2003 posix_openpt(3C)
Check Out this Related Man Page
GRANTPT(3) BSD Library Functions Manual GRANTPT(3) NAME
grantpt, posix_openpt, ptsname, unlockpt -- pseudo-terminal access functions SYNOPSIS
#include <stdlib.h> int grantpt(int fildes); char * ptsname(int fildes); int unlockpt(int fildes); #include <stdlib.h> #include <fcntl.h> int posix_openpt(int oflag); DESCRIPTION
The grantpt(), ptsname(), unlockpt(), and posix_openpt() functions allow access to pseudo-terminal devices. The first three functions accept a file descriptor that references the master half of a pseudo-terminal pair. This file descriptor is created with posix_openpt(). The grantpt() function is used to establish ownership and permissions of the slave device counterpart to the master device specified with fildes. The slave device's ownership is set to the real user ID of the calling process; its permissions are set to user readable-writable and group writable. The group owner of the slave device is also set to the group ``tty'' if it exists on the system; otherwise, it is left untouched. The ptsname() function returns the full pathname of the slave device counterpart to the master device specified with fildes. This value can be used to subsequently open the appropriate slave after posix_openpt() and grantpt() have been called. The unlockpt() function unlocks the slave pseudo-terminal device associated with the master device to which fildes refers. The posix_openpt() function opens the first available master pseudo-terminal device and returns a descriptor to it. The oflag argument spec- ifies the flags used for opening the device: O_RDWR Open for reading and writing. O_NOCTTY If set, do not allow the terminal to become the controlling terminal for the calling process. RETURN VALUES
The grantpt() and unlockpt() functions return the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error. The ptsname() function returns a pointer to the name of the slave device on success; otherwise a NULL pointer is returned and the global variable errno is set to indicate the error. The posix_openpt() function returns a file descriptor to the first available master pseudo-terminal device on success; otherwise -1 is returned and the global variable errno is set to indicate the error. ERRORS
The grantpt(), ptsname(), and unlockpt() functions may fail and set errno to: [EINVAL] fildes is not a master pseudo-terminal device. In addition, the grantpt() function may set errno to: [EACCES] The slave pseudo-terminal device could not be accessed. The posix_openpt() function may fail and set errno to: [EINVAL] oflag consists of an invalid mode bit. [EAGAIN] The system has no available pseudo-terminal devices. The grantpt(), ptsname(), and unlockpt() functions may also fail and set errno for any of the errors specified for the fstat(2) system call. The posix_openpt() function may also fail and set errno for any of the errors specified for the open(2) system call. LEGACY SYNOPSIS
#include <stdlib.h> #include <fcntl.h> int grantpt(int fildes); char * ptsname(int fildes); int unlockpt(int fildes); #include <fcntl.h> int posix_openpt(int oflag); SEE ALSO
open(2), pty(4), tty(4), compat(5) STANDARDS
The grantpt(), ptsname(), unlockpt(), and posix_openpt() functions conform to IEEE Std 1003.1-2001 (``POSIX.1''). BSD
February 2, 2005 BSD