Differential D21206 Diff 62200 lib/libc/stdlib/fdwalk.3

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lib/libc/stdlib/fdwalk.3

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				.\" Copyright (c) 2019 Justin Hibbits
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				.Dd August 9, 2019
				.Dt FDWALK 3
				.Os
				.Sh NAME
				.Nm fdwalk
				.Nd iterate over open file descriptors
				.Sh LIBRARY
				.Lb libc
				.Sh SYNOPSIS
				.In stdlib.h
				.Ft int
				.Fn fdwalk "int (cb)(void , int)" "void *cbd"
				.Sh DESCRIPTION
				The
				.Nm
				function executes a callback for each file descriptor open at the time of its
				invocation.
				kibUnsubmitted Done Inline Actions and _calls_ the callback kib: and _calls_ the callback
				The
				.Nm
				function passes the
				.Ar cbd
				argument into the callback, along with each file descriptor.
				If
				.Ar cbd
				returns non-zero, iteration is terminated.
				It is async-signal-safe.
				.Sh RETURN VALUES
				The
				.Nm
				function always returns 0.
				kibUnsubmitted Done Inline Actions New line for new sentence. malloc(3) etc should be typesetted with .Xr. kib: New line for new sentence. malloc(3) etc should be typesetted with .Xr.
				.Sh SEE ALSO
				.Xr closefrom 2 ,
				.Xr kinfo_getfile 3
				kibUnsubmitted Done Inline Actions Not only new fds not handled (really they could be handled depending on the value), but also closed and thus invalid fds might be passed to callback. The man page lacks explanation of the interface for callback. In particular, what the return value means and how callback should handle errno to make the return state of fdwalk(3) parseable. kib: Not only new fds not handled (really they could be handled depending on the value), but also…
				.Sh HISTORY
				The
				.Nm
				kibUnsubmitted Done Inline Actions This is not quite true. Also, on internal errors from malloc(3) or sysctl(3), you return -1 and errno contains some code. Later you state 'errors are passed through' but I am not sure that this can be understood without looking at the code. kib: This is not quite true. Also, on internal errors from malloc(3) or sysctl(3), you return -1…
				function first appeared in SunOS.
				.Sh BUGS
				It only takes a snapshot, so any file descriptors created or removed
				after the snapshot is taken, either in another thread or in the callback
				function, are not handled.