C错误：对'_itoa'的未定义引用

I'm trying to convert an integer to a character to write to a file, using this line:

我正在尝试将整数转换为字符以写入文件,使用以下行:

fputc(itoa(size, tempBuffer, 10), saveFile);

and I receive this warning and message:

我收到这个警告和消息:

warning: implicit declaration of 'itoa'

警告:'itoa'的隐含声明

undefined reference to '_itoa'

未定义引用'_itoa'

I've already included stdlib.h, and am compiling with:

我已经包含了stdlib.h,并且正在编译:

gcc -Wall -pedantic -ansi

Any help would be appreciated, thank you.

任何帮助将不胜感激,谢谢。

2 个解决方案

#1

itoa is not part of the standard. I suspect either -ansi is preventing you from using it, or it's not available at all.

itoa不是标准的一部分。我怀疑-ansi阻止你使用它,或者它根本不可用。

I would suggest using sprintf()

我建议使用sprintf()

If you go with the c99 standard, you can use snprintf() which is of course safer.

如果你使用c99标准,你可以使用snprintf(),这当然更安全。

char buffer[12];
int i = 20;
snprintf(buffer, 12,"%d",i);

#2

This here tells you that during the compilation phase itoa is unknown:

这里告诉你,在编译阶段itoa是未知的:

warning: implicit declaration of 'itoa'

警告:'itoa'的隐含声明

so if this function is present on your system you are missing a header file that declares it. The compiler then supposes that it is a function that takes an unspecific number of arguments and returns an int.

因此,如果您的系统上存在此功能,则缺少一个声明它的头文件。然后编译器假设它是一个函数,它接受一个非特定数量的参数并返回一个int。

This message from the loader phase

来自加载阶段的此消息

undefined reference to '_itoa'

未定义引用'_itoa'

explains that also the loader doesn't find such a function in any of the libraries he knows of.

解释说,加载器也没有在他知道的任何库中找到这样的功能。

So you should perhaps follow Brian's advice to replace itoa by a standard function.

因此,您应该遵循Brian的建议,用标准函数替换itoa。

#1