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Full Discussion: Unclear pointer and array
Top Forums Programming Unclear pointer and array Post 302884183 by Don Cragun on Saturday 18th of January 2014 07:32:50 AM
Old 01-18-2014
I repeat:
Quote:
because the sizeof(a) in:
Code:
       substring(start, end, text, a, sizeof(a)));

is the size of the pointer; not the number of bytes allocated by malloc() to the array pointed to by a.
And, since you're getting 8 bytes for sizeof(a), we know that you are building your application as a 64-bit app; not as a 32-bit app. You don't want sizeof(a) when a is a pointer; you need to use the number of bytes allocated to the space pointed to by that pointer instead.
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array(3)						     Library Functions Manual							  array(3)

NAME
array - The array library interface SYNTAX
#include <array.h> DESCRIPTION
An allocated array variable keeps track of o a (nonzero) pointer to a dynamically allocated region of memory; o the number of bytes allocated (always positive); and o the number of bytes initialized (between 0 and the number of bytes allocated). There are two other possibilities for the state of an array variable: unallocated and failed. In both cases, there is no dynamically allo- cated region of memory. A new array variable is normally created as a static variable: #include "array.h" static array x; At this point it is unallocated. The array library provides various allocation and inspection functions. A new array variable can also be created dynamically. It must be initialized to all-0, meaning unallocated, before it is given to any of the array functions. It must be returned to the unallocated (or failed) state, for example with array_reset, before it is destroyed. These rules prevent all memory leaks. Expansion and inspection array x; t* p1 = array_allocate(&x,sizeof(t),pos); t* p2 = array_get(&x,sizeof(t),pos); t* p3 = array_start(&x); int64 len = array_length(&x,sizeof(t)); int64 bytes = array_bytes(&x); Truncation and deallocation array x; array_truncate(&x,sizeof(t),len); array_trunc(&x); array_reset(&x); array_fail(&x); Comparison array x; array y; if (array_equal(&x,&y)) /* arrays are equal... */ Concatenation array x; array y; array_cat(&x,&y); array_catb(&x,"fnord",5); array_cats(&x,"fnord"); array_cats0(&x,"fnord"); /* also append the */ array_cat0(&x); /* append */ array_cate(&x,"fnord",1,4); /* append "nor" */ ORIGINAL API DEFINITION
http://cr.yp.to/lib/array.html SEE ALSO
array_get(3), array_start(3), array_fail(3) array(3)
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