用宏处理函数调用或系统调用错误检测

ec.h

#include "/usr/include/stdint.h"    //intptr_t的声明

#define EC_CLEANUP_BGN
    ec_cleanup_bgn:
    {    
    
#define EC_CLEANUP_END
    }
    

//注意__FILE__等是两个下划线
#define ec_cmp(var, target)
    {
        if((intptr_t)(var) == (intptr_t)(target))
        {
            std::cout << __func__ << "[" << __FILE__ << ":" << __LINE__ << "]
";
            goto ec_cleanup_bgn;
        }
    }

#define ec_null(x) ec_cmp(x, NULL)
#define ec_neg1(x) ec_cmp(x, -1)
#define ec_false(x) ec_cmp(x, false)

 main.c

#include "ec.h"

#include <fcntl.h>
#include <unistd.h>

#include <iostream>
#include <cstdlib>
#include <cstdio>

using std::cout;
using std::endl;

bool fcn();

int main(void)
{
    ec_false(fcn());
    
    //exit(EXIT_SUCCESS);
    cout << "EXIT_SUCCESS
";
    return 0;
    
EC_CLEANUP_BGN
    //exit(EXIT_FAILURE);
    cout << "EXIT_FAILURE
";
    return -1;
EC_CLEANUP_END

}

bool fcn()
{
    char* p = NULL;
    int fdin = -1, fdout = -1;
    
    ec_null(p = (char*)malloc(1000));
    ec_neg1(fdin = open("in", O_RDONLY));
    ec_neg1(fdout = open("out", O_WRONLY));
    
    return true;
    
EC_CLEANUP_BGN
    free(p);
    if(fdin != -1)
        (void)close(fdin);
    if(fdout != -1)
        (void)close(fdout);
    return false;
EC_CLEANUP_END

}

记住这种用宏的方式处理函数调用或者系统调用错误检测的实现，虽然这个例子不完善，有BUG。