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Describe standard float/double support.

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Rewrite example to be an interactive session
This commit is contained in:
Guido van Rossum 1997-01-03 04:20:09 +00:00
parent b9a781e177
commit dbadd558b5
2 changed files with 20 additions and 12 deletions
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16
Doc/lib/libstruct.tex
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@ -101,8 +101,8 @@ expression. This is always combined with native byte order.
Standard size and alignment are as follows: no alignment is required Standard size and alignment are as follows: no alignment is required
for any type (so you have to use pad bytes); short is 2 bytes; int and for any type (so you have to use pad bytes); short is 2 bytes; int and
long are 4 bytes. In this mode, there is no support for float and long are 4 bytes. Float and double are 32-bit and 64-bit IEEE floating
double (\code{'f'} and \code{'d'}). point numbers, respectively.
Note the difference between \code{'@'} and \code{'='}: both use native Note the difference between \code{'@'} and \code{'='}: both use native
byte order, but the size and alignment of the latter is standardized. byte order, but the size and alignment of the latter is standardized.
@ -119,10 +119,14 @@ Examples (all using native byte order, size and alignment, on a
big-endian machine): big-endian machine):
\bcode\begin{verbatim} \bcode\begin{verbatim}
from struct import * >>> from struct import *
pack('hhl', 1, 2, 3) == '\000\001\000\002\000\000\000\003' >>> pack('hhl', 1, 2, 3)
unpack('hhl', '\000\001\000\002\000\000\000\003') == (1, 2, 3) '\000\001\000\002\000\000\000\003'
calcsize('hhl') == 8 >>> unpack('hhl', '\000\001\000\002\000\000\000\003')
(1, 2, 3)
>>> calcsize('hhl')
8
>>>
\end{verbatim}\ecode \end{verbatim}\ecode
Hint: to align the end of a structure to the alignment requirement of Hint: to align the end of a structure to the alignment requirement of

16
Doc/libstruct.tex
View file

@ -101,8 +101,8 @@ expression. This is always combined with native byte order.
Standard size and alignment are as follows: no alignment is required Standard size and alignment are as follows: no alignment is required
for any type (so you have to use pad bytes); short is 2 bytes; int and for any type (so you have to use pad bytes); short is 2 bytes; int and
long are 4 bytes. In this mode, there is no support for float and long are 4 bytes. Float and double are 32-bit and 64-bit IEEE floating
double (\code{'f'} and \code{'d'}). point numbers, respectively.
Note the difference between \code{'@'} and \code{'='}: both use native Note the difference between \code{'@'} and \code{'='}: both use native
byte order, but the size and alignment of the latter is standardized. byte order, but the size and alignment of the latter is standardized.
@ -119,10 +119,14 @@ Examples (all using native byte order, size and alignment, on a
big-endian machine): big-endian machine):
\bcode\begin{verbatim} \bcode\begin{verbatim}
from struct import * >>> from struct import *
pack('hhl', 1, 2, 3) == '\000\001\000\002\000\000\000\003' >>> pack('hhl', 1, 2, 3)
unpack('hhl', '\000\001\000\002\000\000\000\003') == (1, 2, 3) '\000\001\000\002\000\000\000\003'
calcsize('hhl') == 8 >>> unpack('hhl', '\000\001\000\002\000\000\000\003')
(1, 2, 3)
>>> calcsize('hhl')
8
>>>
\end{verbatim}\ecode \end{verbatim}\ecode
Hint: to align the end of a structure to the alignment requirement of Hint: to align the end of a structure to the alignment requirement of