请看下面的代码块,在对文件对象调用fclose之前,如何确保该对象未关闭?顺便说一句,调用fclose两次安全吗?
FILE* f = fopen('test.txt')
//some code here, f may be closed by someone, but they may not set it to NULL
...
/// I want to make sure f is not closed before, how can I do it here?
if(...)
{
fclose(f)
我有一个函数,它实现了printf的自定义变体。有人知道我如何用va_list打印多一个参数吗?我的格式类似于"%d some text %s"。我需要a,作为第一个参数打印。
void func (int a, char *fmt, ...) {
va_list ap;
va_start (ap, fmt);
// vprintf(stdout, fmt, a, ap) //Can't do like this :(
vfprintf(fmt, a, ap); //Or like this :(
va_en
我正在使用python,我有这样的数据:
RedHat Enterprise Linux ES 2.1 IA64
RedHat Enterprise Linux ES 2.1
Red Hat Enterprise Linux AS 2.1
Linux kernel 2.6.9
Linux kernel 2.6.8 rc3
Linux kernel 2.6.8 rc1
+ Ubuntu Ubuntu Linux 4.1 ppc
+ Ubuntu Ubuntu Linux 4.1 ia64
Linux kernel 2.6.8
我想把这个信息存储在一个json file.but
嗨,我一直在努力寻找解决这个问题的方法,但我找不到。我需要安装模块'IO::EventMux',所以我使用:
cpan[1]> install IO::EventMux
然而,我得到了以下错误:
Catching error: "CPAN::Exception::yaml_process_error=HASH(0xe34ed78)" at /usr/local/share/perl/5.14.2/CPAN.pm line 392
CPAN::shell() called at /usr/local/share/perl/5.14.2/App/Cpa