Berkeley CSUA MOTD:Entry 12861
Berkeley CSUA MOTD
 
WIKI | FAQ | Tech FAQ
http://csua.com/feed/
2018/09/20 [General] UID:1000 Activity:popular
9/20    

2004/3/25-26 [Computer/SW/Languages/C_Cplusplus] UID:12861 Activity:nil
3/25    Please confirm:
        int foo(void) {
          static char *str = (char*) malloc(10000 * sizeof(char));
          ...
        }
        malloc will only be called once, correct?
        \_ It will be called everytime the function is called.
           You may want to look at __attribute__((constructor)) if
           you are using gcc.
           \_ Uh, if it were evaluated every time the function is called, the
              "static" keyword would be totally useless.  To the OP, if you're
              using ANSI C, that's not a legal construct.  Static variables
              are equivalent to global variables with restricted scope, so you
              can't initialize them to non-constant values.  It's fine in C++;
              C++ initializes static variables at run-time.  If you're using
              C++, though, you probably ought to use new instead of malloc, or
              there are probably better ways to do whatever it is you want to
              do.
        \_ you easily can test this by replacing the malloc call with
           printf/cout/whatever.
2018/09/20 [General] UID:1000 Activity:popular
9/20    

You may also be interested in these entries...
2014/1/14-2/5 [Computer/SW/Languages/C_Cplusplus] UID:54763 Activity:nil
1/14    Why is NULL defined to be "0" in C++ instead of "((void *) 0)" like in
        C?  I have some overloaded functtions where one takes an integer
        parameter and the other a pointer parameter.  When I call it with
        "NULL", the compiler matches it with the integer version instead of
        the pointer version which is a problem.  Other funny effect is that
        sizeof(NULL) is different from sizeof(myPtr).  Thanks.
	...
2011/3/7-4/20 [Computer/SW/Languages/C_Cplusplus] UID:54056 Activity:nil
3/7     I have a C question.  I have the following source code in two identical
        files t.c and t.cpp:
                #include <stdlib.h>
                int main(int argc, char *argv[]) {
                  const char * const * p1;
                  const char * * p2;
	...
2009/7/21-24 [Computer/SW/Languages/Java] UID:53168 Activity:moderate
7/20    For those who care btw, it looks like eclipse is now A Standard Tool
        at UCB ugrad cs, probably replaced emacs.  Furthermore, people get
        angry at seeing Makefiles, (since eclispe takes care of that).  I
        guess it's just a sign of the times.
        \_ The more people at my work use eclipse the less the code is
           managable in emacs.  I'm not sure which application's fault
	...
2005/2/15-16 [Computer/SW/Languages/C_Cplusplus, Computer/SW/Compilers] UID:36174 Activity:moderate
2/15    Technical question:  we have a memory leak in our C code, we think,
        but it's not the sort of memory leak where the memory's unreferenced.
        What we'd like to do is sort of a poor-man's profile, we want
        to know who calls our memory allocator "New"...  Sorta like a stack
        trace.  Using an actual profiler is sort of difficult 'cause it's
        a parallel application.  Thanks,  --peterm
	...
2004/9/23 [Computer/SW/Languages/C_Cplusplus] UID:33716 Activity:high
9/23    Is the a C++ equivelent to the C realloc function?
        \_ realloc(). But seriously, maybe you want an STL container
           that automatically grows.
           \_ Not in this case.  I just need to grow a char array
              automatically myself.   (For speed reasons) Really, It's a
              very isolated place in the code, and I'll probably just end
	...
2004/8/10-11 [Computer/SW/Languages/C_Cplusplus, Computer/SW/Compilers] UID:32805 Activity:high
8/10    C question.  Is there anything wrong with the following?
        const my_struct_t **pp;
        pp = malloc(sizeof(my_struct_t *));
        pp = realloc(pp, sizeof (my_struct_t *) * 2);
        "gcc -Wall" doesn't complain.  But the M$ compiler (cl.exe) complains
        about the realloc line:
	...
2004/4/13-14 [Computer/SW/Languages/C_Cplusplus] UID:13175 Activity:high
4/13    How much C++/C knowledge do recent Berkeley CS/EECS grad have?
        \_ Class CSGrad inherits FromDaddy and does not implement C++Knowledge
           very well.
           \_ funny.  just the rich and poor as always.  the middle class can't
              afford education.
        \_ They know how to deal with pointers and addresses, malloc and free.
	...
2003/12/4-5 [Computer/SW/Languages/C_Cplusplus] UID:11317 Activity:nil
12/4    Is there any reason to worry about mixing the usage of malloc and new?
        Obviously, you can't delete() malloc'd memory (and vv), but aside from
        that, will bad things happen?  Oh, I should note that this is for a C
        library that is used by C++ -- a coworker suggested wrapping my memory
        allocations (and deletions) with
        #ifdef __cplusplus
	...
2003/1/18-19 [Computer/SW/Languages/C_Cplusplus] UID:27139 Activity:very high
1/17    If I have "foo_bar_baz_struct_t *p, *q;", which of the following
        is better?
        1.      p = malloc(sizeof (foo_bar_baz_struct_t));
                memcpy(q, p, sizeof (foo_bar_baz_struct_t));
        2.      p = malloc(sizeof *p);
                memcpy(q, p, sizeof *p);
	...
2001/2/27 [Computer/SW/Languages/C_Cplusplus, Computer/HW/Memory] UID:20713 Activity:high
2/26    Hey folks, I'm looking for something like Purify but cheap.
        What do people do for C programming to guard against memory
        bashing and leaks, other than write their own malloc and
        buy expensive software from Rational?
        \_ wasn't there some kind of program to analyze C code for
           no no's. I think it was called something like lint.
	...
2001/1/25-26 [Computer/SW/Languages/C_Cplusplus] UID:20431 Activity:high
1/25    C question.  I want to declare a variable p which stores the pointer to
        a malloc'ed array of 65536 elements.  Each of these 65536 elements
        in turn stores the pointer to a malloc'ed array or 16 int's.  What's
        the best way to declare p to include as much type information as
        possible?  Sure I can do "int ***p;", but that doesn't contain much
        type information.  Thanks.
	...
2000/2/11-13 [Computer/SW/Languages/C_Cplusplus] UID:17485 Activity:very high
2/10    I get an impression that new grads coming out of berkeley don't
        have much exposure to C.  I mean pure C, not C++.  How do most
        people feel about this?  I guess I'm asking alumni who are hiring
        and also current students.
        \_ I've spent the last year doing project in only C or Java, no C++.
        \_ they don't necessarily have much exposure to C++ either...
	...