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Do not modify the value returned by the getenv() function. Create a copy and make your changes locally, using setenv() to update the environment when necessary. This allows the implementation to properly allocate and manage memory.

Non-Compliant Code Example

This non-compliant code example showing that modification of the string value returned by the function getenv(). Characters in env should not be changed directly.

int foo()
{
    char *env;
    env = getenv("TEST_ENV");
    env[0] = 'a';

    /*Do some more things*/

    return 0;
}

Compliant Code Solution

This is a compliant code solution. If it is necessary to modify the value of the string returned by the function getenv(), then the programmer should make a local copy of that string value, and then modify the local copy of that string. If it is necessary to propagate the changes back to the environment, use setenv().

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References

\[[ISO/IEC 9899-1999|AA. C References#ISO/IEC 9899-1999]\] Section 7.20.4.5, "The {{getenv}} function"
\[[Open Group 04|AA. C References#Open Group 04]\] [getenv|http://www.opengroup.org/onlinepubs/000095399/functions/getenv.html]