blocks|key|1024607|text|snprintf不是C89的一部分。它只在C99中是标准的。微软有no+plan+supporting+C99。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1024608|(但它也是C%2B%2B0x中的标准...！)|1024609|有关解决方法，请参阅下面的其他答案。|1024610|entityMap|0|LINK|mutability|MUTABLE|url|http://connect.microsoft.com/VisualStudio/feedback/details/333273/request-for-c99-vla-in-visual-studio^0|0|8|X|M|0|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]]|D|@$9|U|A|V|1|W]]|E|$]]|$1|F|3|G|5|6|7|X|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|Y|8|@]|D|@]|E|$]]|$1|J|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|K|$L|$5|M|N|O|E|$P|Q]]]]

<code>snprintf</code> is not part of C89. It's standard only in C99. Microsoft has <a href="http://connect.microsoft.com/VisualStudio/feedback/details/333273/request-for-c99-vla-in-visual-studio" rel="noreferrer">no plan supporting C99</a>.

(But it's also standard in C++0x...!)

See other answers below for a workaround.

blocks|key|1239495|text|如果不需要返回值，也可以将snprintf定义为_snprintf_s|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1239496|#define+snprintf(buf,len,+format,...)+_snprintf_s(buf,+len,len,+format,+__VA_ARGS__)|code-block|syntax|javascript|1239497|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If you don't need the return value, you could also just define snprintf as _snprintf_s

<pre><code>#define snprintf(buf,len, format,...) _snprintf_s(buf, len,len, format, __VA_ARGS__)
</code></pre>

blocks|key|1239273|text|我相信视窗的等价物是sprintf_s|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1239274|entityMap^0|A|9|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

I believe the Windows equivalent is <code>sprintf_s</code>

blocks|key|1024677|text|ffmpeg提供了snprintf()和vsnprintf()的另一个安全替代品。您可以查看source+here+(建议)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1024678|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/FFmpeg/FFmpeg/blob/master/compat/msvcrt/snprintf.c^0|9|A|K|B|1A|B|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]|$9|Q|A|R|B|C]]|D|@$9|S|A|T|1|U]]|E|$]]|$1|F|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

Another safe replacement of <code>snprintf()</code> and <code>vsnprintf()</code> is provided by ffmpeg. You can checkout the <a href="https://github.com/FFmpeg/FFmpeg/blob/master/compat/msvcrt/snprintf.c" rel="nofollow">source here</a> (suggested).

blocks|key|1239569|text|我尝试了@Valentin+Milea的代码，但遇到了访问冲突错误。对我来说唯一起作用的是疯狂编码的实现：http://asprintf.insanecoding.org/|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1239570|具体地说，我使用的是VC%2B%2B2008遗留代码。从Insane+Coding的实现(可以从上面的链接下载)中，我使用了三个文件：asprintf.c、asprintf.h和vasprintf-msvc.c。其他文件用于MSVC的其他版本。|style|CODE|1239571|为完整起见，编辑内容如下：|1239572|asprintf.h：|1239573|#ifndef+INSANE_ASPRINTF_H
#define+INSANE_ASPRINTF_H

#ifndef+__cplusplus
#include+<stdarg.h>
#else
#include+<cstdarg>
extern+"C"
{
#endif

#define+insane_free(ptr)+{+free(ptr);+ptr+=+0;+}

int+vasprintf(char+**strp,+const+char+*fmt,+va_list+ap);
int+asprintf(char+**strp,+const+char+*fmt,+...);

#ifdef+__cplusplus
}
#endif

#endif|code-block|syntax|javascript|1239574|asprintf.c：|1239575|#include+"asprintf.h"

int+asprintf(char+**strp,+const+char+*fmt,+...)
{
++int+r;
++va_list+ap;
++va_start(ap,+fmt);
++r+=+vasprintf(strp,+fmt,+ap);
++va_end(ap);
++return(r);
}|1239576|vasprintf-msvc.c：|1239577|#include+<stdio.h>
#include+<stdlib.h>
#include+<limits.h>
#include+"asprintf.h"

int+vasprintf(char+**strp,+const+char+*fmt,+va_list+ap)
{
++int+r+=+-1,+size+=+_vscprintf(fmt,+ap);

++if+((size+>=+0)+&&+(size+<+INT_MAX))
++{
++++*strp+=+(char+*)malloc(size%2B1);+//%2B1+for+null
++++if+(*strp)
++++{
++++++r+=+vsnprintf(*strp,+size%2B1,+fmt,+ap);++//%2B1+for+null
++++++if+((r+<+0)+%7C%7C+(r+>+size))
++++++{
++++++++insane_free(*strp);
++++++++r+=+-1;
++++++}
++++}
++}
++else+{+*strp+=+0;+}

++return(r);
}|1239578|用法(疯狂编码提供的test.c的一部分)：|1239579|#include+<stdio.h>
#include+<stdlib.h>
#include+"asprintf.h"

int+main()
{
++char+*s;
++if+(asprintf(&s,+"Hello,+%25d+in+hex+padded+to+8+digits+is:+%2508x\n",+15,+15)+!=+-1)
++{
++++puts(s);
++++insane_free(s);
++}
}|1239580|entityMap|0|LINK|mutability|MUTABLE|url|http://asprintf.insanecoding.org/^0|1H|X|0|0|1R|A|22|A|2D|G|0|0|0|0|0|0|0|0|A|6|0|0^^$0|@$1|2|3|4|5|6|7|1A|8|@]|9|@$A|1B|B|1C|1|1D]]|C|$]]|$1|D|3|E|5|6|7|1E|8|@$A|1F|B|1G|F|G]|$A|1H|B|1I|F|G]|$A|1J|B|1K|F|G]]|9|@]|C|$]]|$1|H|3|I|5|6|7|1L|8|@]|9|@]|C|$]]|$1|J|3|K|5|6|7|1M|8|@]|9|@]|C|$]]|$1|L|3|M|5|N|7|1N|8|@]|9|@]|C|$O|P]]|$1|Q|3|R|5|6|7|1O|8|@]|9|@]|C|$]]|$1|S|3|T|5|N|7|1P|8|@]|9|@]|C|$O|P]]|$1|U|3|V|5|6|7|1Q|8|@]|9|@]|C|$]]|$1|W|3|X|5|N|7|1R|8|@]|9|@]|C|$O|P]]|$1|Y|3|Z|5|6|7|1S|8|@$A|1T|B|1U|F|G]]|9|@]|C|$]]|$1|10|3|11|5|N|7|1V|8|@]|9|@]|C|$O|P]]|$1|12|3|-4|5|6|7|1W|8|@]|9|@]|C|$]]]|13|$14|$5|15|16|17|C|$18|19]]]]

I tried @Valentin Milea's code but I've got access violation errors. The only thing that worked for me was Insane Coding's implementation: <a href="http://asprintf.insanecoding.org/" rel="nofollow noreferrer">http://asprintf.insanecoding.org/</a>

Specifically, I was working with VC++2008 legacy code. From Insane Coding's implementation (can be downloaded from the link above), I used three files: <code>asprintf.c</code>, <code>asprintf.h</code> and <code>vasprintf-msvc.c</code>. Other files were for other versions of MSVC.

[EDIT] For completeness, their contents are as follows:

asprintf.h:

<pre><code>#ifndef INSANE_ASPRINTF_H
#define INSANE_ASPRINTF_H

#ifndef __cplusplus
#include &lt;stdarg.h&gt;
#else
#include &lt;cstdarg&gt;
extern "C"
{
#endif

#define insane_free(ptr) { free(ptr); ptr = 0; }

int vasprintf(char **strp, const char *fmt, va_list ap);
int asprintf(char **strp, const char *fmt, ...);

#ifdef __cplusplus
}
#endif

#endif
</code></pre>

asprintf.c:

<pre><code>#include "asprintf.h"

int asprintf(char **strp, const char *fmt, ...)
{
 int r;
 va_list ap;
 va_start(ap, fmt);
 r = vasprintf(strp, fmt, ap);
 va_end(ap);
 return(r);
}
</code></pre>

vasprintf-msvc.c:

<pre><code>#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;limits.h&gt;
#include "asprintf.h"

int vasprintf(char **strp, const char *fmt, va_list ap)
{
 int r = -1, size = _vscprintf(fmt, ap);

 if ((size &gt;= 0) &amp;&amp; (size &lt; INT_MAX))
 {
 *strp = (char *)malloc(size+1); //+1 for null
 if (*strp)
 {
 r = vsnprintf(*strp, size+1, fmt, ap); //+1 for null
 if ((r &lt; 0) || (r &gt; size))
 {
 insane_free(*strp);
 r = -1;
 }
 }
 }
 else { *strp = 0; }

 return(r);
}
</code></pre>

Usage (part of <code>test.c</code> provided by Insane Coding): 

<pre><code>#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include "asprintf.h"

int main()
{
 char *s;
 if (asprintf(&amp;s, "Hello, %d in hex padded to 8 digits is: %08x\n", 15, 15) != -1)
 {
 puts(s);
 insane_free(s);
 }
}
</code></pre>

I'm unfortunate enough to be stuck using VS 2010 for a project, and noticed the following code still doesn't build using the non-standards compliant compiler:

<pre><code>#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;

int main (void)
{
 char buffer[512];

 snprintf(buffer, sizeof(buffer), "SomeString");

 return 0;
}
</code></pre>

(fails compilation with the error: C3861: 'snprintf': identifier not found)

I remember this being the case way back with VS 2005 and am shocked to see it still hasn't been fixed.

Does any one know if Microsoft has any plans to move their standard C libraries into the year 2010?

snprintf and Visual Studio 2010

编译器

不幸的是，我在一个项目中使用VS2010，并注意到以下代码仍然不能使用非标准兼容的编译器构建：#include <stdio.h>#include <stdlib.h>int main (void){ char buffer[512]; snprintf(buffer, sizeof(buffer), "SomeString"); return 0;}(编译失败，错误为: C38

问snprintf和Visual Studio 2010
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