When to use Malloc? Post: 86623

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Top Forums Programming When to use Malloc? Post 86623 by blowtorch on Sunday 16th of October 2005 11:48:43 PM

10-17-2005

Registered User

Quote:

What actually happens if I don't malloc space for the strings, (in the situation as mentioned in my previous post), and the strings that the array points to change all the time. What about the space the old strings occupy, will that automaticly be free space, or will it be occupied until the program terminates?

I really haven't got your question, but will try to answer just the same,
If you declare a character array for strings like char a[50], then you can have the string that occupies it change frequently over the course of your program, but as long as it does not go over 50*sizeo(char) bytes, it wont matter. The space that the old string occupies will be overwritten by the new one.
Note that the question of freeing space does not come up, as you have statically allocated memory. It will be freed only when you exit the program.

--NOTE--
The use of the word 'statically' does not mean that you are declaring any of the variables as static.

Code:

static int a;

is different from

Code:

 int a;

--/NOTE--

Last edited by blowtorch; 10-17-2005 at 10:58 AM.. Reason: fix broken tag

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tcl_concat

Tcl_Concat(3)						      Tcl Library Procedures						     Tcl_Concat(3)

__________________________________________________________________________________________________________________________________________________

NAME

       Tcl_Concat - concatenate a collection of strings

SYNOPSIS

       #include <tcl.h>

       const char *
       Tcl_Concat(argc, argv)

ARGUMENTS

       int argc (in)			      Number of strings.

       const char *const argv[] (in)	      Array of strings to concatenate.	Must have argc entries.
_________________________________________________________________

DESCRIPTION

       Tcl_Concat is a utility procedure used by several of the Tcl commands.  Given a collection of strings, it concatenates them together into a
       single string, with the original strings separated by spaces.  This procedure behaves differently than Tcl_Merge, in that the arguments are
       simply  concatenated:  no  effort  is made to ensure proper list structure.  However, in most common usage the arguments will all be proper
       lists themselves;  if this is true, then the result will also have proper list structure.

       Tcl_Concat eliminates leading and trailing white space as it copies strings from argv to the result.  If an element  of	argv  consists	of
       nothing but white space, then that string is ignored entirely.  This white-space removal was added to make the output of the concat command
       cleaner-looking.

       The result string is dynamically allocated using Tcl_Alloc;  the caller must eventually release the space by calling Tcl_Free.

SEE ALSO

       Tcl_ConcatObj

KEYWORDS

       concatenate, strings

Tcl									7.5							     Tcl_Concat(3)

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