怎样才能打印为size_t变量可移植使用printf系列？ [英] How can one print a size_t variable portably using the printf family?

问题描述

我型为size_t 的变量，我想用的printf打印出来（）。我用什么格式说明可移植打印？

I have a variable of type size_t, and I want to print it using printf(). What format specifier do I use to print it portably?

在32位机，％U 似乎是正确的。我用g ++的-g -W -Wall -ansi -Werror -pedantic编制，也没有警告。但是，当我编译code在64位机，它产生的警告。

In 32-bit machine, %u seems right. I compiled with g++ -g -W -Wall -Werror -ansi -pedantic, and there was no warning. But when I compile that code in 64-bit machine, it produces warning.

size_t x = <something>;
printf( "size = %u\n", x );

warning: format '%u' expects type 'unsigned int', 
    but argument 2 has type 'long unsigned int'

警告消失，如预期，如果我更改为鲁％。

现在的问题是，我怎么能写code，所以它编译于32位和64位的机器没有警告的？

The question is, how can I write the code, so that it compiles warning free on both 32- and 64- bit machines?

编辑：我猜一个答案可能是中投变到无符号长，和使用打印％禄。这将在这两种情况下工作。我找是否有任何其他的想法。

I guess one answer might be to "cast" the variable into an unsigned long, and print using %lu. That would work in both cases. I am looking if there is any other idea.

推荐答案

使用以Z 修改

size_t x = ...;
ssize_t y = ...;
printf("%zu\n", x);  // prints as unsigned decimal
printf("%zx\n", x);  // prints as hex
printf("%zd\n", y);  // prints as signed decimal

这篇关于怎样才能打印为size_t变量可移植使用printf系列？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！