projects / babeltrace.git / blame
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| 6dc2ca62 MD |
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 |