What happens when C exits after a pointer was overriden

This is a discussion on What happens when C exits after a pointer was overriden within the C Programming forums, part of the General Programming Boards category; Hi, Suppose pA is a pointer to dynamic allocated memory using calloc. Now I override pA, so pA no longer ...

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    What happens when C exits after a pointer was overriden

    Hi,
    Suppose pA is a pointer to dynamic allocated memory using calloc. Now I override pA, so pA no longer holds the address of the allocated memory (I know there is a memory leak, but that is not the point). After the program exits (free was not used), does it free the allocated memory made earlier ?

    In order that upon exit, the allocated memory be free, must pA hold the address to the allocated memory ?

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    Quote Originally Posted by Salem View Post
    Thanks, that answered part of my question. The part that still needs an answer is :
    pA was overridden before there was a chance to use free. upon exit, the OS clears the memory, even if free was not used. In order that the OS can free the memory must pA hold the address to the allocated memory ?
    Last edited by David20132013; 07-02-2013 at 02:19 AM.

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    No, it's not necessary. The OS gives the program a block of memory. Think of it as one large chunk. When the program terminates, ALL that large chunk of memory, is available (free'd), to the OS, for use by any other program.

    Memory leaks are really a problem when the program leaking memory, runs for a long(er) time. Eventually, the chunk of memory available to the program runs low, causing the system to run very slowly as it starts using available swap space on the hard drive, as RAM (very slow). Finally, the program will crash.

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    Quote Originally Posted by Adak View Post
    No, it's not necessary. The OS gives the program a block of memory. Think of it as one large chunk. When the program terminates, ALL that large chunk of memory, is available (free'd), to the OS, for use by any other program.

    Memory leaks are really a problem when the program leaking memory, runs for a long(er) time. Eventually, the chunk of memory available to the program runs low, causing the system to run very slowly as it starts using available swap space on the hard drive, as RAM (very slow). Finally, the program will crash.
    Thank you

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