title: Getenv() error when invoked more than one time
body: <p>I have codes to get environment variable name from stand input and call library function <code>getenv()</code> to get the value and output.</p>
  
  <p>Here are codes.</p>
  
  <pre><code>#include &lt;stdio.h&gt;
  #include &lt;string.h&gt;
  #include &lt;stdlib.h&gt;
  
  #define MAXLEN 256
  
  int main(void)
  
  {
      char *envName;
      char *envValue;
      char *envEntry;
      char *envVar=(char*)malloc(sizeof(char)*MAXLEN);
  
      while(NULL!=(envName=gets(envVar))){
  
      envValue=getenv(envName);
      if(envValue){
          printf("%s\n",envValue);
  
          envEntry=strtok(envValue,";");
  
          while(envEntry){
              printf("%s\n",envEntry);
  
              envEntry=strtok(NULL,";");
          }
      }else{
          printf("not found\n");
      }
  }
  
      return 0;
  }
  </code></pre>
  
  <p>If the environment variable <code>"path"</code> contains <code>"a;b;c;d"</code>.
  While it runs,if type a string "path" first time,it works well,but if type "path" again it only gets the first string like<code>"a"</code> or <code>"a;b"</code>.</p>