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authorFred Drake <fdrake@acm.org>1998-07-23 21:18:25 (GMT)
committerFred Drake <fdrake@acm.org>1998-07-23 21:18:25 (GMT)
commitcf0fb8bfeef0cbbf00b99c272f6de8c3d48573e8 (patch)
tree12c8195d5aaebab34e5896f671ed54c732ef46d0 /Doc
parentc457ca7ede3033f69320ce81c33cacdd2db057f7 (diff)
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Document the 'p' format character.
Clean up some of the markup.
Diffstat (limited to 'Doc')
-rw-r--r--Doc/lib/libstruct.tex23
1 files changed, 16 insertions, 7 deletions
diff --git a/Doc/lib/libstruct.tex b/Doc/lib/libstruct.tex
index 22595cb..08b930c 100644
--- a/Doc/lib/libstruct.tex
+++ b/Doc/lib/libstruct.tex
@@ -55,6 +55,7 @@ and Python values should be obvious given their types:
\lineiii{f}{float}{float}
\lineiii{d}{double}{float}
\lineiii{s}{char[]}{string}
+ \lineiii{p}{char[]}{string}
\end{tableiii}
A format character may be preceded by an integral repeat count; e.g.\
@@ -63,7 +64,7 @@ the format string \code{'4h'} means exactly the same as \code{'hhhh'}.
Whitespace characters between formats are ignored; a count and its
format must not contain whitespace though.
-For the \code{'s'} format character, the count is interpreted as the
+For the \character{s} format character, the count is interpreted as the
size of the string, not a repeat count like for the other format
characters; e.g. \code{'10s'} means a single 10-byte string, while
\code{'10c'} means 10 characters. For packing, the string is
@@ -72,7 +73,15 @@ For unpacking, the resulting string always has exactly the specified
number of bytes. As a special case, \code{'0s'} means a single, empty
string (while \code{'0c'} means 0 characters).
-For the \code{'I'} and \code{'L'} format characters, the return
+The \character{p} format character can be used to encode a Pascal
+string. The first byte is the length of the stored string, with the
+bytes of the string following. If count is given, it is used as the
+total number of bytes used, including the length byte. If the string
+passed in to \function{pack()} is too long, the stored representation
+is truncated. If the string is too short, padding is used to ensure
+that exactly enough bytes are used to satisfy the count.
+
+For the \character{I} and \character{L} format characters, the return
value is a Python long integer.
By default, C numbers are represented in the machine's native format
@@ -91,7 +100,7 @@ according to the following table:
\lineiii{!}{network (= big-endian)}{standard}
\end{tableiii}
-If the first character is not one of these, \code{'@'} is assumed.
+If the first character is not one of these, \character{@} is assumed.
Native byte order is big-endian or little-endian, depending on the
host system (e.g. Motorola and Sun are big-endian; Intel and DEC are
@@ -105,16 +114,16 @@ for any type (so you have to use pad bytes); short is 2 bytes; int and
long are 4 bytes. Float and double are 32-bit and 64-bit IEEE floating
point numbers, respectively.
-Note the difference between \code{'@'} and \code{'='}: both use native
+Note the difference between \character{@} and \character{=}: both use native
byte order, but the size and alignment of the latter is standardized.
-The form \code{'!'} is available for those poor souls who claim they
+The form \character{!} is available for those poor souls who claim they
can't remember whether network byte order is big-endian or
little-endian.
There is no way to indicate non-native byte order (i.e. force
-byte-swapping); use the appropriate choice of \code{'<'} or
-\code{'>'}.
+byte-swapping); use the appropriate choice of \character{<} or
+\character{>}.
Examples (all using native byte order, size and alignment, on a
big-endian machine):