Parsing Question

This is a discussion on Parsing Question within the C Programming forums, part of the General Programming Boards category; Hey guys I'm working on a function Code: void *copydirectory(void *arg) which is passed two consecutive strings separated by null ...

  1. #1
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    Parsing Question

    Hey guys I'm working on a function
    Code:
    void *copydirectory(void *arg)
    which is passed two consecutive strings separated by null character, these strings are directory names that I need later in the function to open a directory. I was thinking I could use,
    Code:
     char *strtok(char *str, const char *delim);
    or rather
    Code:
    char *strtok_r(char *str, const char *delim, char **saveptr);
    since my function needs to be thread safe. Can I use a null character as a delimiter? For example,
    Code:
    char **saveptr;
    char *dir1, *dir2;
    char *delim = '\0';
    dir1 = strtok_r(arg, delim, &saveptr);
    dir2 = strtok_r(NULL,delim, &saveptr);
    Additionally, would the names being pointed to be non null terminated after the calls to strtok_r? Any tips on other strategies would help.

  2. #2
    cas
    cas is offline
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    No, this will not work. Since the null character marks the end of a string, strtok() wouldn't know that you're overloading its meaning.

    Since you just have two strings concatenated, it's easy to pull them apart:
    Code:
    char arg[] = "/foo\0/bar";
    char *first, *second;
    first = arg;
    second = arg + strlen(arg) + 1;

  3. #3
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    Jun 2009
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    10
    I see. Thanks for your input.

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