Dealing with strings containing embedded null characters

This is a discussion on Dealing with strings containing embedded null characters within the C Programming forums, part of the General Programming Boards category; hi, how can I get the length of a string that has embedded '

  1. #1
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    Dealing with strings containing embedded null characters

    hi,

    how can I get the length of a string that has embedded '\0' ?

    Code:
    char * foo = "abcde\0fgh\0ijkl"; 
    printf ("%s\n", foo);            /* this only prints out: abcde */ 
    printf("%d\n", strlen(foo));  /* this displays: 5 instead of 12 (or is it 14 ?) */
    Thanks
    --Andrew

  2. #2
    and the hat of wrongness Salem's Avatar
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    You'd have to define your own terminator, say a double null, and write a set of functions to deal with such a thing.

    Code:
    char * foo = "abcde\0fgh\0ijkl\0";
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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  3. #3
    and the Hat of Guessing tabstop's Avatar
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    There is no such a thing as a string that has an embedded \0. By definition, a string stops at a \0 character.

    What are you actually trying to accomplish?

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    What i'm trying to do is read and display the contents of a file, specifically "/proc/<pid>/cmdline"
    file (file size happens to be 0-bytes) on Linux. The contents of "cmdline" file contain embedded '\0' characters
    and represent the command line arguments for a given process. The '\0' character is the delimiter of each argument.

    Thanks
    --Andrew
    Last edited by mr_c; 10-29-2008 at 01:01 AM.

  5. #5
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    Quote Originally Posted by mr_c View Post
    What i'm trying to do is read and display the contents of a file, specifically "/proc/<pid>/cmdline"
    file (file size happens to be 0-bytes) on Linux. The contents of "cmdline" file contain embedded '\0' characters
    and represent the command line arguments for a given process. The '\0' character is the delimiter of each argument.

    Thanks
    --Andrew
    I expect that follows the same concept as environment variables: It has a double zero at the end. Use "od -x /proc/<pid>/cmdline" to display it in hex, and I believe you will see the end is two zero bytes.

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