From 78ab0c7ba942491cc406da598a2de56092fea773 Mon Sep 17 00:00:00 2001 From: Shawn Landden Date: Sun, 31 Dec 2017 20:12:59 -0800 Subject: [PATCH] copy_file_range: glibc provides a user-space emulation where the system call is absent Signed-off-by: Shawn Landden Signed-off-by: Michael Kerrisk --- man2/copy_file_range.2 | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/man2/copy_file_range.2 b/man2/copy_file_range.2 index facb16ba7..a836ce5cc 100644 --- a/man2/copy_file_range.2 +++ b/man2/copy_file_range.2 @@ -27,7 +27,7 @@ copy_file_range \- Copy a range of data from one file to another .SH SYNOPSIS .nf -.B #include +.B #define _GNU_SOURCE .B #include .PP .BI "ssize_t copy_file_range(int " fd_in ", loff_t *" off_in , @@ -135,12 +135,13 @@ are not on the same mounted filesystem. .SH VERSIONS The .BR copy_file_range () -system call first appeared in Linux 4.5. -Library support was added in glibc 2.27. +system call first appeared in Linux 4.5, but glibc 2.27 provides a user-space +emulation when it is not available. +.\" https://sourceware.org/git/?p=glibc.git;a=commit;f=posix/unistd.h;h=bad7a0c81f501fbbcc79af9eaa4b8254441c4a1f .SH CONFORMING TO The .BR copy_file_range () -system call is a nonstandard Linux extension. +system call is a nonstandard Linux and GNU extension. .SH NOTES If .I file_in