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POUsing to strcpy() to get parts of a char* causes a program crash
 

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  1. POUsing to strcpy() to get parts of a char* causes a program crash
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    <p>I am trying to grab bits from a char* then store it in a map. I use strcpy &amp; strncpy to do this but my program crashes when I go to use strncpy (it compiles but crashes at runtime).</p> <p>Why is my program crashing &amp; how can I successfully grab bits from the char* and store them in a map?</p> <p><strong>EDIT: after taking advice I have initialised the char* but it still crashes?</strong></p> <pre><code>// I did the following char* variable = ""; char* value = ""; map &lt;string, string&gt; GetEvironmentVariablesEx() { map &lt;string, string&gt; envVariables; char* environVar = GetEnvironmentStrings(); char* pos = strchr( environVar, '\0' ); // This is what environVar contains: environVar = "=::=::\0APPDATA=c:/users/user1/desktop\0OS=windowsNT\0\0"; // note the string is double null terminated // Skip over the "=::=::\0" of the environVar string if ( pos != NULL ) { environVar = ++pos; pos = strchr( environVar, '\0' ); } else return envVariables; while ( true ) { char* delim = strchr( environVar, '=' ); char* variable; char* value; if ( delim == NULL ) { printf("Environment variable string is badly formatted"); break; } // The crash occurs at the below line: the crash occurs at runtime strncpy( variable, environVar, strlen(delim) ); strcpy( value, environVar+strlen(delim) ); printf( "Variable is: %s = %s \n", variable, value ); envVariables.insert( pair&lt;string, string&gt;(string(variable), string(value)) ); environVar = ++pos; // find the "\0\0" that identifies the end of environVar if ( pos != NULL &amp;&amp; *pos == 0 ) { break; } pos = strchr( environVar, '\0' ); } FreeEnvironmentStrings( environVar ); return envVariables; } </code></pre>
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    1. COWhy are you so insistent upon using the harder-to-use `<cstring>` functions instead of the C++ `std::string` functionality?
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      1. POUsing to strcpy() to get parts of a char* causes a program crash
      1. USJames McNellis
    2. COUnder what circumstance do you imagine that `strchr(environVar, '\0')` would ever return NULL?
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      1. POUsing to strcpy() to get parts of a char* causes a program crash
      1. USRob Kennedy
 

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