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| author | mckay <mckay@FreeBSD.org> | 1997-03-09 13:16:48 +0000 |
|---|---|---|
| committer | mckay <mckay@FreeBSD.org> | 1997-03-09 13:16:48 +0000 |
| commit | 0df49cb9cfc20544d5a22327db106151826ea246 (patch) | |
| tree | 1155d675c47c2b4a076bfe0112eaab542a1fb28a /lib/libc/sys/dup.2 | |
| parent | 01b8721dc82dd688e63a96a5d4488a7b53b3bad4 (diff) | |
| download | FreeBSD-src-0df49cb9cfc20544d5a22327db106151826ea246.zip FreeBSD-src-0df49cb9cfc20544d5a22327db106151826ea246.tar.gz | |
Clarified the behaviour of dup2(fd1,fd2) when fd1==fd2 and when fd1 is invalid.
Safe for 2.2!
Diffstat (limited to 'lib/libc/sys/dup.2')
| -rw-r--r-- | lib/libc/sys/dup.2 | 25 |
1 files changed, 21 insertions, 4 deletions
diff --git a/lib/libc/sys/dup.2 b/lib/libc/sys/dup.2 index 66c9d29..58a967d 100644 --- a/lib/libc/sys/dup.2 +++ b/lib/libc/sys/dup.2 @@ -30,7 +30,7 @@ .\" SUCH DAMAGE. .\" .\" @(#)dup.2 8.1 (Berkeley) 6/4/93 -.\" $Id$ +.\" $Id: dup.2,v 1.7 1997/02/22 15:03:49 peter Exp $ .\" .Dd June 4, 1993 .Dt DUP 2 @@ -92,10 +92,27 @@ In .Fn dup2 , the value of the new descriptor .Fa newd -is specified. If this descriptor is already -in use, the descriptor is first deallocated as if a +is specified. If this descriptor is already in use and +.Fa oldd +!= +.Fa newd , +the descriptor is first deallocated as if a .Xr close 2 -call had been done first. +call had been used. +If +.Fa oldd +is not a valid descriptor, then +.Fa newd +is not closed. +If +.Fa oldd +== +.Fa newd +and +.Fa oldd +is a valid descriptor, then +.Fn dup2 +is successful, and does nothing. .Sh IMPLEMENTATION NOTES .Pp In the non-threaded library |
