From: Wang Nan <[email protected]>
Subject: [PATCH 3/4] makedumpfile: add -D_GNU_SOURCE to CFLAGS
Date: Sat, 26 Apr 2014 12:07:08 +0800
> This patch is preparation for introduce pread/pwrite.
>
Do you explain more about _GNU_SOURCE? Did you need to define this on
your environment to build makedumpfile with pread/pwrite?
I tried to build a very simple test program using pread like
int main(void)
{
printf("%p\n", pread);
}
on RHEL5.4, RHEL6.5 and fc20, and all were done successfully without
_GNU_SOURCE. They are all on x86_64.
I checked man pread and man pwrite on each environments for
_GNU_SOURCE but I didn't find it. What I found was _XOPEN_SOURCE
description only. For example this is man pread on RHEL6.5.
$ LANG=C man pread
PREAD(2) Linux Programmer's Manual PREAD(2)
NAME
pread, pwrite - read from or write to a file descriptor at a given offset
SYNOPSIS
#define _XOPEN_SOURCE 500
#include <unistd.h>
ssize_t pread(int fd, void *buf, size_t count, off_t offset);
ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset);
Note that just as I said the above, building was successfully done on
this environment.
--
Thanks.
HATAYAMA, Daisuke
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