c - 如何避免在 Linux 上的 strftime() 中调用过多的 stat(/etc/localtime)？

Question

我让我的一个记录处理程序在 strace 下运行了几分钟。

这表明在那几分钟内对 stat("/etc/localtime",..) 的调用超过 200 000 000 次，这听起来有点过分和不必要。

strace 输出如下所示:

write(1, "C137015 393393093052629137110 47"..., 16384) = 16384
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
stat("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2225, ...}) = 0
read(0, "\224q\1\207\0\0\202\1\4\203\1\4\204\1\1\205\1\1\206\1\7\207\1\6\211\1\22\212\1\22\213\1"..., 16384) = 16384

实际上，对于处理的每条记录，结果都是 1 次 stat() 调用，而罪魁祸首竟然是这一行非常普通的代码

strftime(call->date_time,DATELEN,"%Y%m%d %H%M%S",&tm_buf);

那么 - 我怎样才能避免 strftime() 在每次调用时调用 stat(/etc/localtime)？

Answer 1

这样做可能是因为您的时区未设置。 strftime 查询 /etc/localtime 来找到它。

尝试设置 TZ 环境变量。

这是 a link for that behavior .