Here is a last case about pointers i found. CASE 1 ------- When a C++ function does not malloc any memory it may return a pointer. In this case we can do
DIM pPointer as Pointer pPointer = Alloc(4096)' alloc 4096 bytes pPointer = getwd(pBuf) 'use pPointer with Str@() or other xxx@() Free(pPointer) pPointer=0 OK! CASE 2 ------- When a c++ function itself allocate memory with malloc() what can we do? Example. -------- ' Gambas module file 'char *get_current_dir_name(void); Extern get_current_dir_name() As Pointer In "libc:6" Public Sub Main() Dim pFunc As Pointer Dim sWorkingDirectory As String 'get_current_dir_name pFunc = Alloc(4096) Print pFunc '0xc12938 pFunc = get_current_dir_name() Print pFunc '0xc147a0 'now we cannot Free(pFunc) it is not 0xc12938 anymore 'get_current_dir_name() malloc itself memory and return a new pointer sWorkingDirectory = Str@(pFunc) Print sWorkingDirectory ' Free(pFunc) 'if i unrem Free i get a crash, because i try to free the 0xc147a0 pFunc = 0 End What can we do in such cases when a function itself allocates memory? Should we free it? Can we? May be we can use pointers without Alloc()? Example, no Alloc(), no Free, just DIM pPointer --------- ' Gambas module file 'char *get_current_dir_name(void); Extern get_current_dir_name() As Pointer In "libc:6" Public Sub Main() Dim pFunc As Pointer Dim sWorkingDirectory As String 'get_current_dir_name pFunc = get_current_dir_name() Print pFunc '0xc147a0 sWorkingDirectory = Str@(pFunc) Print sWorkingDirectory pFunc = 0 End ------------------------------------------------------------------------------ Protect Your Site and Customers from Malware Attacks Learn about various malware tactics and how to avoid them. Understand malware threats, the impact they can have on your business, and how you can protect your company and customers by using code signing. http://p.sf.net/sfu/oracle-sfdevnl _______________________________________________ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
