Tcl_Alloc(3) Tcl Library Procedures Tcl_Alloc(3) _________________________________________________________________________________________________ NAME Tcl_Alloc, Tcl_Free, Tcl_Realloc, Tcl_AttemptAlloc, Tcl_AttemptRealloc, ckalloc, ckfree, ckrealloc, attemptckalloc, attemptckrealloc - allocate or free heap memory SYNOPSIS #include <tcl.h> char * Tcl_Alloc(size) void Tcl_Free(ptr) char * Tcl_Realloc(ptr, size) char * Tcl_AttemptAlloc(size) char * Tcl_AttemptRealloc(ptr, size) char * ckalloc(size) void ckfree(ptr) char * ckrealloc(ptr, size) char * attemptckalloc(size) char * attemptckrealloc(ptr, size) ARGUMENTS int size (in) Size in bytes of the memory block to allocate. char *ptr (in) Pointer to memory block to free or realloc. _________________________________________________________________ DESCRIPTION These procedures provide a platform and compiler independent interface for memory alloca- tion. Programs that need to transfer ownership of memory blocks between Tcl and other modules should use these routines rather than the native malloc() and free() routines pro- vided by the C run-time library. Tcl_Alloc returns a pointer to a block of at least size bytes suitably aligned for any use. Tcl_Free makes the space referred to by ptr available for further allocation. Tcl_Realloc changes the size of the block pointed to by ptr to size bytes and returns a pointer to the new block. The contents will be unchanged up to the lesser of the new and old sizes. The returned location may be different from ptr. Tcl_AttemptAlloc and Tcl_AttemptRealloc are identical in function to Tcl_Alloc and Tcl_Realloc, except that Tcl_AttemptAlloc and Tcl_AttemptRealloc will not cause the Tcl interpreter to panic if the memory allocation fails. If the allocation fails, these func- tions will return NULL. Note that on some platforms, attempting to allocate a block of memory will also cause these functions to return NULL. The procedures ckalloc, ckfree, ckrealloc, attemptckalloc, and attemptckrealloc are imple- mented as macros. Normally, they are synonyms for the corresponding procedures documented on this page. When Tcl and all modules calling Tcl are compiled with TCL_MEM_DEBUG defined, however, these macros are redefined to be special debugging versions of of these procedures. To support Tcl's memory debugging within a module, use the macros rather than direct calls to Tcl_Alloc, etc. KEYWORDS alloc, allocation, free, malloc, memory, realloc, TCL_MEM_DEBUG Tcl 7.5 Tcl_Alloc(3)