diff options
| -rw-r--r-- | man2/getcpu.2 | 31 |
1 files changed, 21 insertions, 10 deletions
diff --git a/man2/getcpu.2 b/man2/getcpu.2 index a75123f971..59089bd746 100644 --- a/man2/getcpu.2 +++ b/man2/getcpu.2 @@ -14,10 +14,10 @@ getcpu \- determine CPU and NUMA node on which the calling thread is running .SH SYNOPSIS .nf -.B #include <linux/getcpu.h> +.BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */" +.B #include <sched.h> .PP -.BI "int getcpu(unsigned int *" cpu ", unsigned int *" node \ -", struct getcpu_cache *" tcache ); +.BI "int getcpu(unsigned int *" cpu ", unsigned int *" node ); .fi .SH DESCRIPTION The @@ -37,10 +37,6 @@ or .I node is NULL nothing is written to the respective pointer. .PP -The third argument to this system call is nowadays unused, -and should be specified as NULL -unless portability to Linux 2.6.23 or earlier is required (see NOTES). -.PP The information placed in .I cpu is guaranteed to be current only at the time of the call: @@ -82,16 +78,31 @@ The intention of .BR getcpu () is to allow programs to make optimizations with per-CPU data or for NUMA optimization. +.\" +.SS C library/kernel differences +The kernel system call has a third argument: +.PP +.in +4n +.nf +.BI "int getcpu(unsigned int *" cpu ", unsigned int *" node , +.BI " struct getcpu_cache *" tcache ); +.fi +.in .PP The .I tcache -argument is unused since Linux 2.6.24. +argument is unused since Linux 2.6.24, +and (when invoking the system call directly) +should be specified as NULL, +unless portability to Linux 2.6.23 or earlier is required. +.PP .\" commit 4307d1e5ada595c87f9a4d16db16ba5edb70dcb1 .\" Author: Ingo Molnar <mingo@elte.hu> .\" Date: Wed Nov 7 18:37:48 2007 +0100 .\" x86: ignore the sys_getcpu() tcache parameter -In earlier kernels, -if this argument was non-NULL, +In Linux 2.6.23 and earlier, if the +.I tcache +argument was non-NULL, then it specified a pointer to a caller-allocated buffer in thread-local storage that was used to provide a caching mechanism for .BR getcpu (). |