diff options
Diffstat (limited to '')
| -rw-r--r-- | man2/dup.2 | 22 |
1 files changed, 11 insertions, 11 deletions
@@ -14,7 +14,7 @@ .\" details for dup2(). .\" 2008-10-09, mtk: add description of dup3() .\" -.TH dup 2 2023-05-03 "Linux man-pages 6.05.01" +.TH dup 2 2023-10-31 "Linux man-pages 6.7" .SH NAME dup, dup2, dup3 \- duplicate a file descriptor .SH LIBRARY @@ -23,14 +23,14 @@ Standard C library .SH SYNOPSIS .nf .B #include <unistd.h> -.PP +.P .BI "int dup(int " oldfd ); .BI "int dup2(int " oldfd ", int " newfd ); -.PP +.P .BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */" .BR "#include <fcntl.h>" " /* Definition of " O_* " constants */" .B #include <unistd.h> -.PP +.P .BI "int dup3(int " oldfd ", int " newfd ", int " flags ); .fi .SH DESCRIPTION @@ -43,7 +43,7 @@ open file description as the descriptor .BR open (2).) The new file descriptor number is guaranteed to be the lowest-numbered file descriptor that was unused in the calling process. -.PP +.P After a successful return, the old and new file descriptors may be used interchangeably. Since the two file descriptors refer to the same open file description, @@ -52,7 +52,7 @@ for example, if the file offset is modified by using .BR lseek (2) on one of the file descriptors, the offset is also changed for the other file descriptor. -.PP +.P The two file descriptors do not share file descriptor flags (the close-on-exec flag). The close-on-exec flag @@ -74,14 +74,14 @@ the file descriptor .I newfd is adjusted so that it now refers to the same open file description as .IR oldfd . -.PP +.P If the file descriptor .I newfd was previously open, it is closed before being reused; the close is performed silently (i.e., any errors during the close are not reported by .BR dup2 ()). -.PP +.P The steps of closing and reusing the file descriptor .I newfd are performed @@ -97,7 +97,7 @@ might be reused between the two steps. Such reuse could happen because the main program is interrupted by a signal handler that allocates a file descriptor, or because a parallel thread allocates a file descriptor. -.PP +.P Note the following points: .IP \[bu] 3 If @@ -233,7 +233,7 @@ also sometimes returns .B EINVAL like .BR F_DUPFD . -.PP +.P If .I newfd was open, any errors that would have been reported at @@ -249,7 +249,7 @@ before calling .BR dup2 (), because of the race condition described above. Instead, code something like the following could be used: -.PP +.P .in +4n .EX /* Obtain a duplicate of \[aq]newfd\[aq] that can subsequently |