[babeltrace.git] / std-ext-lib.txt

Common Trace Format - Standards, Extensions and Libraries
Mathieu Desnoyers
September 26, 2010

This document describes the CTF library dependencies on standards, extensions
and libraries.


** Standards

* C99

This library is C99 compliant. A non-documented non-compliance should be
reported as a bug. See the ISO/IEC 9899:TC2 publication:

  http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf


* IEEE 754-2008

The IEEE 754-2008 standard is used for binary floating point arithmetic
representation. See:

  http://grouper.ieee.org/groups/754/


* GNU/C extensions

This library uses some widely GNU/C extensions widely adopted by compilers.
For detail, see:

  http://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html#C-Extensions


** Non-standard Dependencies

In some cases, standards do not provide the required primitives to write
portable code; these are listed here.


* Non-standard endian.h

endian.h is used to provide the following definitions:

#define LITTLE_ENDIAN	1234
#define BIG_ENDIAN	4321
#define BYTE_ORDER	/* Your architecture: BIG_ENDIAN or LITTLE_ENDIAN */


* Bitfields

The ISO/IEC 9899 standard leaves bitfields implementation defined, which is
unacceptable for portability of this library. Section 6.7.2.1 - "Structure and
union specifiers", Semantic 10 specifically indicates that padding and order of
bit-fields allocation within a unit is implementation-defined.

This is why this library provides the bitfield.h header (under the MIT license),
which specifies bitfields write primitives that uses the same field order as the
GNU/C compiler, but does not require any padding for fields spreading across
units. This is therefore a superset of the GNU/C bitfields, which can be dealt
with by detecting C structure padding manually given the bit offset and
bit-field size as well as the unit size.


** Libraries

* The GLib library of C routines

The library glib 2 is used for its basic data structures. See

  http://library.gnome.org/devel/glib/2.24/glib-data-types.html
Commit	Line	Data
	1	Common Trace Format - Standards, Extensions and Libraries
	2	Mathieu Desnoyers
	3	September 26, 2010
	4
	5	This document describes the CTF library dependencies on standards, extensions
	6	and libraries.
	7
	8
	9	** Standards
	10
	11	* C99
	12
	13	This library is C99 compliant. A non-documented non-compliance should be
	14	reported as a bug. See the ISO/IEC 9899:TC2 publication:
	15
	16	http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf
	17
	18
	19	* IEEE 754-2008
	20
	21	The IEEE 754-2008 standard is used for binary floating point arithmetic
	22	representation. See:
	23
	24	http://grouper.ieee.org/groups/754/
	25
	26
	27	* GNU/C extensions
	28
	29	This library uses some widely GNU/C extensions widely adopted by compilers.
	30	For detail, see:
	31
	32	http://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html#C-Extensions
	33
	34
	35
	36	** Non-standard Dependencies
	37
	38	In some cases, standards do not provide the required primitives to write
	39	portable code; these are listed here.
	40
	41
	42	* Non-standard endian.h
	43
	44	endian.h is used to provide the following definitions:
	45
	46	#define LITTLE_ENDIAN 1234
	47	#define BIG_ENDIAN 4321
	48	#define BYTE_ORDER /* Your architecture: BIG_ENDIAN or LITTLE_ENDIAN */
	49
	50
	51	* Bitfields
	52
	53	The ISO/IEC 9899 standard leaves bitfields implementation defined, which is
	54	unacceptable for portability of this library. Section 6.7.2.1 - "Structure and
	55	union specifiers", Semantic 10 specifically indicates that padding and order of
	56	bit-fields allocation within a unit is implementation-defined.
	57
	58	This is why this library provides the bitfield.h header (under the MIT license),
	59	which specifies bitfields write primitives that uses the same field order as the
	60	GNU/C compiler, but does not require any padding for fields spreading across
	61	units. This is therefore a superset of the GNU/C bitfields, which can be dealt
	62	with by detecting C structure padding manually given the bit offset and
	63	bit-field size as well as the unit size.
	64
	65
	66	** Libraries
	67
	68	* The GLib library of C routines
	69
	70	The library glib 2 is used for its basic data structures. See
	71
	72	http://library.gnome.org/devel/glib/2.24/glib-data-types.html