Question

我正在以下列方式打印我的断言声明：

assert((i==0) && "i is not zero");
Output: Assertion 'i==0 && i is not zero' failed.


What I want to be printed:
Output: 'i==0, i is not zero failed.

Answer 1

你必须编写自己的断言宏。类似的东西：

#include <stdio.h>
#include <stdlib.h>

#undef myassert

#ifndef NDEBUG
#define myassert(test, why) ((test) ? (void) 0                      \
                             : (fprintf(stderr, "%s, %s failed.\n", \
                                        #test, why), abort()))
#else
#define myassert(test, why) ((void) 0)
#endif

并像这样使用它：

myassert(i == 0, "i is not zero");

Answer 2

然后编写自己的断言宏。（Ninja＆＃39; by Ross Ridge。）我的例子，根据Jonathan Leffler的评论进行了大量修改：

#undef my_assert
#ifdef NDEBUG
#define my_assert(expression, errormessage) ((void)0)
#else

#include <stdlib.h>
#include <stdio.h>

#if __STDC_VERSION__-199901L >= 0
#define my_assert(expr, msg) \
    ((void)( (expr) ? 0 : do_assert(__FILE__, __LINE__, __func__, msg) ))

#elif defined(__GNUC__)
#define my_assert(expr, msg) \
    ((void)( (expr) ? 0 : do_assert(__FILE__, __LINE__, __FUNCTION__, msg) ))

#else
#define my_assert(expr, msg) \
    ((void)( (expr) ? 0 : do_assert(__FILE__, __LINE__, NULL, msg) ))
#endif

#ifndef HAVE_DO_ASSERT
#define HAVE_DO_ASSERT
static inline int do_assert(const char *const filename,
                            const unsigned long linenum,
                            const char *const funcname,
                            const char *const msg)
{
    if (funcname)
        fprintf(stderr, "%s: Line %lu, function %s(): %s\n", filename, linenum, funcname, msg);
    else
        fprintf(stderr, "%s: Line %lu: %s\n", filename, linenum, msg);
    abort();
    return 0;
}
#endif

#endif

如果您使用

my_assert(i == 0, "nonzero i!");

在main()第25行的example.c功能中，i非零，您将获得

example.c: Line 25, function main(): nonzero i!

标准错误（加上Aborted.之类的内容，具体取决于操作系统和C库）。

如何在没有“＆amp;＆amp;”的情况下打印断言语句？

2 个答案: