malloc appends an exclamation point?

This is a discussion on malloc appends an exclamation point? within the C Programming forums, part of the General Programming Boards category; I'm just starting to program in C, and my program is being difficult. I am working on a text parser ...

  1. #1
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    malloc appends an exclamation point?

    I'm just starting to program in C, and my program is being difficult. I am working on a text parser to make it easier to do some sabremetrics on the teams in my fantasy baseball league (woo!). Generally, I am parsing specific pieces of a text file into an array of structs which store a string. The structs are defined as:

    Code:
    struct team_roster_t{
       char* team_name;
    }team_roster_t;
    and initialized as:

    Code:
    #define NUMTEAMS 12
    ...
    struct team_roster_t* teams = malloc(NUMTEAMS*sizeof(struct team_roster_t));
    The team names are then set in a while loop by:

    Code:
    /*char* team  is set with some file and string functions that I know correctly retrieve the team name.*/
    
    int namesize = strlen(team);
    teams[i].team_name = malloc(namesize);
    strcpy(teams[i].team_name, team);
    I'm running into the peculiar problem that when my program executes the malloc for the fourth team name (Quaker Goats), it additionally appends an exclamation point to the third team name (Biddlestar Galactica --> Biddlestar Galactica!). I know via gdb that the team_name field for the Biddlestar is set correctly when it is initialized, without an exclamation point. I also know that the ! appears as soon as malloc() is called a second time, before the fourth team name ("Quaker Goats") is copied (via strcpy) to the newly malloc()ed address.

    There are no exclamation points anywhere in the input .txt file, nor are there any strings with an "!" in my code. Since the '!' appears following an unrelated malloc, I'm assuming it's some sort of memory leak, but I can't seem to find any indication that an ! would result from this sort of error.

    I'm happy to post more code or answer anything I wasn't clear about. Hope someone can help!

  2. #2
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    Code:
    int namesize = strlen(team);
    teams[i].team_name = malloc(namesize);
    strlen() does not include terminating null character.
    And strlen() returns size_t.
    Code:
      size_t namesize = strlen(team) + 1 ; // +1 for '\0'
      team[i].team_name = malloc(namesize);
      if( team[i].name_name == NULL )

  3. #3
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    Of course! Still not sure how an exclamation point got there--I'm sure it's some artifact of the ascii code and the header for the next string. Won't worry too much about it though. Thanks!

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    This time it may be exclamation point. next time it may be '?'

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