TINFO(3) Library Functions Manual TINFO(3) NAME tinfo -- self-(de)allocating thread-local data structures LIBRARY PDEL Library (libpdel, -lpdel) SYNOPSIS #include <pthread.h> #include <pdel/util/tinfo.h> TINFO_INIT(type, mtype, initfunc); void * tinfo_get(struct tinfo *t); int tinfo_set(struct tinfo *t, const void *data); int tinfo_set_nocopy(struct tinfo *t, void *data); DESCRIPTION These functions provide support for thread-local data structures defined by structs(3) types that are automatically initialized and destroyed. A thread-local data structure is described by a static or global struct tinfo; each such structure must be initialized with the TINFO_INIT() macro. For example: static struct tinfo foo_info = TINFO_INIT(&foo_type, "foo", fooinit); type is the structs(3) type for the data structure, mtype is the typed_mem(3) type used to allocate memory to hold each thread's instance, and initfunc is an optional instance initializer function of this type: typedef int tinfo_init_t(struct tinfo *t, void *data); initfunc() should initialize the data structure pointed to by data as an instance of type (which will also be available as t->type). The memory pointed to by data will have been allocated with typed_mem(3) type mtype but will be otherwise uninitialized. If initfunc is NULL, then structs_init(3) is used to initialize the data structure to the default value defined by type. Instances of tinfo thread-local data structure are automatically destroyed when the associated thread exits, by calling structs_free(type, NULL, data) and then FREE(mtype, data). tinfo_get() returns the current thread's instance of the data structure. If this is the thread's first invocation of tinfo_get(), a new instance is automatically allocated and initialized. The caller should not free the returned value, but may modify it in a way consistent with its structs(3) type. tinfo_set() sets the current thread's data structure instance to be a copy of data, made using structs_get(3). The original data is unmodified and remains the caller's responsibility to free. Any existing thread-local data structure instance is automatically replaced and freed. tinfo_set_nocopy() is equivalent to tinfo_set() except that no copy of data is made; therefore, data must point to heap memory allocated with typed_mem(3) type mtype (also available as t->mtype) and the caller should not dereference data once tinfo_set_nocopy() has returned successfully. Both tinfo_set() and tinfo_set_nocopy() may take a NULL data parameter; this causes any existing thread-local data structure instance to be freed so that the next call to tinfo_get() will cause a new instance to be con- structed. RETURN VALUES tinfo_get(), tinfo_set(), and tinfo_set_nocopy() return NULL or -1 with errno set appropriately to indicate an error. SEE ALSO libpdel(3), structs(3), typed_mem(3) HISTORY The PDEL library was developed at Packet Design, LLC. http://www.packetdesign.com/ AUTHORS Archie Cobbs <archie@freebsd.org> FreeBSD ports 15.quarterly April 22, 2002 TINFO(3)
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | SEE ALSO | HISTORY | AUTHORS
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