c++ - 为什么断言在这里不起作用？

Question

代码如下:

#include <Rcpp.h>
#include <iostream>
#include <assert.h>
#include <stdio.h>

using namespace Rcpp;


// [[Rcpp::export]]
double eudist(NumericVector x, NumericVector y) {
    int nx = x.size();
    int ny = y.size();
    std::cout << nx << '\n' << ny << std::endl;
    assert(nx == ny);

    double dist=0;
    for(int i = 0; i < nx; i++) {
        dist += pow(x[i] - y[i], 2);
    }

    return sqrt(dist);
}

将其采购到 R 后，我得到以下结果，显然它在出现错误时不会中止:

#////////////////////////////////////////////////////
sourceCpp('x.cpp')
#////////////////////////////////////////////////////
eudist(c(0, 0), c(1, 1))
2
2
[1] 1.4142
#////////////////////////////////////////////////////
eudist(c(0, 0), c(1, 1, 1))
2
3
[1] 1.4142

Answer 1

请注意，assert() 等被明确禁止用于 CRAN 上传。引用自 CRAN Repo Policy页:

The code and examples provided in a package should never do anything which might be regarded as malicious or anti-social. The following are illustrative examples from past experience.

• Compiled code should never terminate the R process within which it is running. Thus C/C++ calls to assert/abort/exit, Fortran calls to STOP and so on must be avoided. Nor may R code call q().

所以关于 Debug模式的答案在技术上是正确的，但也请注意，如果您计划在某个时候上传 CRAN，则不应该使用它。