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-rw-r--r--man3/stdin.312
1 files changed, 10 insertions, 2 deletions
diff --git a/man3/stdin.3 b/man3/stdin.3
index 42d027175b..ef72cfdd05 100644
--- a/man3/stdin.3
+++ b/man3/stdin.3
@@ -2,6 +2,7 @@
.\"
.\" This man page was written in 1998 by David A. Holland
.\" and placed in the Public Domain. Polished a bit by aeb.
+.\" 2005-06-16 mtk, mentioned freopen()
.\"
.Dd March 24, 1998
.Dt STDIN 3
@@ -48,14 +49,21 @@ interface, that is, the functions like
.Xr read 2
and
.Xr lseek 2 .
-The integer file descriptors associated with the streams
+.Pp
+On program startup, the integer file descriptors
+associated with the streams
.Nm stdin ,
.Nm stdout ,
and
.Nm stderr
-are 0, 1, and 2, respectively. The preprocessor symbols STDIN_FILENO,
+are 0, 1, and 2, respectively.
+The preprocessor symbols STDIN_FILENO,
STDOUT_FILENO, and STDERR_FILENO are defined with these values in
<unistd.h>.
+(Applying
+.Xr freopen 3
+to one of these streams can change the file descriptor number
+associated with the stream.)
.Pp
Note that mixing use of FILEs and raw file descriptors can produce
unexpected results and should generally be avoided.