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pkopen(3) [v7 man page]

PKOPEN(3)						     Library Functions Manual							 PKOPEN(3)

NAME
pkopen, pkclose, pkread, pkwrite, pkfail - packet driver simulator SYNOPSIS
char *pkopen(fd) pkclose(ptr) char *ptr; pkread(ptr, buffer, count) char *ptr, *buffer; pkwrite(ptr, buffer, count) char *ptr, *buffer; pkfail() DESCRIPTION
These routines are a user-level implementation of the full-duplex end-to-end communication protocol described in pk(4). If fd is a file descriptor open for reading and writing, pkopen carries out the initial synchronization and returns an identifying pointer. The pointer is used as the first parameter to pkread, pkwrite, and pkclose. Pkread, pkwrite and pkclose behave analogously to read, write and close(2). However, a write of zero bytes is meaningful and will produce a corresponding read of zero bytes. SEE ALSO
pk(4), pkon(2) DIAGNOSTICS
Pkfail is called upon persistent breakdown of communication. Pkfail must be supplied by the user. Pkopen returns a null (0) pointer if packet protocol can not be established. Pkread returns -1 on end of file, 0 in correspondence with a 0-length write. BUGS
This simulation of pk(4) leaves something to be desired in needing special read and write routines, and in not being inheritable across calls of exec(2). Its prime use is on systems that lack pk. These functions use alarm(2); simultaneous use of alarm for other puposes may cause trouble. deprecated PKOPEN(3)

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Tcl_Alloc(3)						      Tcl Library Procedures						      Tcl_Alloc(3)

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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
unsigned 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 allocation. 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 provided 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. If ptr is NULL, this is equivalent to calling Tcl_Alloc with just the size argument. 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 functions will return NULL. Note that on some platforms, but not all, attempting to allocate a zero-sized block of memory will also cause these functions to return NULL. The procedures ckalloc, ckfree, ckrealloc, attemptckalloc, and attemptckrealloc are implemented 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, how- ever, these macros are redefined to be special debugging versions 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)
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