structures and allocation

This is a discussion on structures and allocation within the C Programming forums, part of the General Programming Boards category; Code: struct person { int age; char* name; }; I've always used to work with this kind of structures like ...

  1. #1
    Registered User Micko's Avatar
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    structures and allocation

    Code:
    struct person
    {
    	int age;
    	char* name;
    };
    I've always used to work with this kind of structures like this:
    Code:
    int main ( void )
    {
    	struct person per;
    	/* some code */
    	per.name = malloc ( strlen ( "Test" ) + 1 );
    	strcpy ( per.name, "Test" )
    	/* some code */
    }
    I always first allocate memory, but often I see this form:
    Code:
    /*...*/
    	per.name = "Test"
    /*...*/
    Is there any problem with the latter way? I think there is but...
    Can you comment this?

    Thanks
    Last edited by Micko; 12-02-2005 at 01:47 AM.
    Gotta love the "please fix this for me, but I'm not going to tell you which functions we're allowed to use" posts.
    It's like teaching people to walk by first breaking their legs - muppet teachers! - Salem

  2. #2
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    Code:
    per.name = "Test"
    Depending on your compiler "test" may reside in memory that is marked as read only. You shouldn't try to alter this and shouldn't try to free this memory.

  3. #3
    Registered User Micko's Avatar
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    That's Ok, but will that cause possible problems with segmentation faults??
    Gotta love the "please fix this for me, but I'm not going to tell you which functions we're allowed to use" posts.
    It's like teaching people to walk by first breaking their legs - muppet teachers! - Salem

  4. #4
    Bond sunnypalsingh's Avatar
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    Quote Originally Posted by Micko
    That's Ok, but will that cause possible problems with segmentation faults??
    not untill you try to modify it

  5. #5
    Sr. Software Engineer filker0's Avatar
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    To be more specific, every structure references the same copy of the string "test". In many systems, string literals (that is, source-level quoted strings) are stored as read-only data, so any attempt to modify the string will either cause a segmentation fault of some sort or modify the name string for each person struct initialized in this manner.
    Insert obnoxious but pithy remark here

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