将一个va_list作为参数传递给另一个 [英] Passing one va_list as a parameter to another
问题描述
我使用fastcgi库创建一个应用程序,他们的打印方法有点冗长。我试图将他们的fprintf函数包装在我自己的方法中:
I'm creating an application using the fastcgi library, and their method of printing is a little verbose. I'm trying to wrap their fprintf function in my own method:
我想转动
FCGX_FPrintF(out,char * fmt,...);
FCGX_FPrintF(out, char* fmt, ...);
到
write(char * strFormat,...);
write(char* strFormat, ...);
发现了va_list的魔力,但找不到一个简单的方法来传递va_list值到他们的fprintf函数。有办法做到这一点吗?我知道vsprintf和vprintf存在,所以它必须比我想象的更难。
I've found the magic of va_list but can't find an easy way to pass va_list values into their fprintf function. Is there a way to do this? I know vsprintf and vprintf exist so it must be harder than I imagine it is.
如果所有其他失败,我只是重载一个写函数
If all else fails, I'll just overload a write function
推荐答案
您必须在Fast CGI库中找到 vfprintf()
的类比。至少有一个合理的可能性,有一个;实现 FCGX_FPrintF()
的简单方法是:
You would have to find the analogue of vfprintf()
in the Fast CGI library. It is at least moderately plausible that there is one; the easy way to implement FCGX_FPrintF()
is:
void FCGX_FPrintF(FILE *out, char *fmt, ...)
{
va_list args;
va_start(args, fmt);
FCGX_VFPrintF(out, fmt, args);
va_end(args);
}
所以很有可能函数存在;您需要检查它是否正式公开。
So it is highly probable that the function exists; you will need to check whether it is exposed officially or not.
快速访问 Fast CGI网站揭示了FCGX前缀由fgciapp.h头中声明的函数使用,并且依次包含:
A quick visit to the Fast CGI web site reveals that the FCGX prefix is used by functions declared in the fgciapp.h header, and that in turn contains:
/*
*----------------------------------------------------------------------
*
* FCGX_FPrintF, FCGX_VFPrintF --
*
* Performs printf-style output formatting and writes the results
* to the output stream.
*
* Results:
* number of bytes written for normal return,
* EOF (-1) if an error occurred.
*
*----------------------------------------------------------------------
*/
DLLAPI int FCGX_FPrintF(FCGX_Stream *stream, const char *format, ...);
DLLAPI int FCGX_VFPrintF(FCGX_Stream *stream, const char *format, va_list arg);
所以,接口已经完成了。
So, there's the function with the interface completed.
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