segmentation fault?

sgm · 01-25-2003, 03:55 PM

I am writing a CGI program for RedHat Linux 7.2 and came across a strange problem (segmentation fault) when running my program. The problem is also exhibited when running from the bash shell prompt so I have eliminated all of the CGI functionality to try to get to the root of the problem. Here is a simple program that exhibits the problem:

//filename test.cc
#include <stdio.h>
#include <algorithm>
#include <string>

using namespace std;

int main(int argc, char *argv[])
{
string strMethod = getenv("REQUEST_METHOD");

return 0;
}

It was compiled using a makefile containing this:

all:test

test: test.o
g++ -o test test.o

test.o: test.cc
g++ -Wall -c -o test.o test.cc

I would really appreciate any insight that anyone can provide.

Thanks,

sgm

crabboy · 01-25-2003, 08:41 PM

Looks like the environment variable REQUEST_METHOD never exists. You are calling the string constructor on a NULLpointer. This code will not cause a seg faut.

Code:

#include <stdio.h>
#include <algorithm>
#include <string>
#include <iostream.h>

using namespace std;

int main(int argc, char *argv[])
{
   int iSize;
   char * pEnv;

   if (( pEnv = getenv("REQUEST_METHOD" )) == NULL )
   {
      cout << "Env variable REQUEST_METHOD does not exist" << endl;
   }
   else
   {
     string strMethod( getenv("REQUEST_METHOD"));
     cout << "String is :" << strMethod.c_str() << endl;
   }
return 0;
}