diff options
Diffstat (limited to 'Doc/lib/libstruct.tex')
| -rw-r--r-- | Doc/lib/libstruct.tex | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/Doc/lib/libstruct.tex b/Doc/lib/libstruct.tex index 6de67cccf5..8d0ae60e12 100644 --- a/Doc/lib/libstruct.tex +++ b/Doc/lib/libstruct.tex @@ -94,13 +94,17 @@ 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). -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. +The \character{p} format character encodes a "Pascal string", meaning +a short variable-length string stored in a fixed number of bytes. +The count is the total number of bytes stored. The first byte stored is +the length of the string, or 255, whichever is smaller. The bytes +of the string follow. If the string passed in to \function{pack()} is too +long (longer than the count minus 1), only the leading count-1 bytes of the +string are stored, If the string is shorter than count-1, it is padded +with null bytes so that exactly count bytes in all are used. Note that +for \function{unpack()}, the \character{p} format character consumes count +bytes, but that the string returned can never contain more than 255 +characters. For the \character{I}, \character{L}, \character{q} and \character{Q} format characters, the return value is a Python long integer. |