unlockpt - Unlocks a pseudoterminal master and slave pair
Standard C Library (libc.so, libc.a)
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Specifies a file descriptor that is returned from a successful open of the master pseudoterminal device.
The unlockpt() function unlocks a slave pseudoterminal from its associated master counterpart. It does this by clearing a lock flag so that the slave device can be opened.
Upon successful completion, the unlockpt() function returns a value of 0. Otherwise, it returns a value of -1 and sets errno to indicate the error.
The unlockpt() function sets errno to the specified values for the following conditions:
The file descriptor specified by the mastfd parameter is not an open file descriptor. The file descriptor specified by the mastfd parameter is not associated with a master pseudoterminal device.
Guides: System V Compatibility User's Guide delim off