Template             Description
a                    An ASCII string (null padded)
A                    An ASCII string (space padded)
b                    A bit string (low-to-high order, like vec)
B                    A bit string (high-to-low order)
c                    A signed char value
C                    An unsigned char value
d                    A double-precision float in the native format
f                    A single-precision float in the native format
h                    A hexadecimal string (low nybble first, to high)
H                    A hexadecimal string (high nybble first)
i                    A signed integer
I                    An unsigned integer
l                    A signed long value
L                    An unsigned long value
n                    A short in "network" (big-endian) order
N                    A long in "network" (big-endian) order
p                    A pointer to a null-terminated string
P                    A pointer to a structure (fixed-length string)
q                    A signed 64-bit value
Q                    An unsigned 64-bit value
s                    A signed short value (16-bit)
S                    An unsigned short value (16-bit)
u                    A uuencoded string
v                    A short in "VAX" (little-endian) order
V                    A long in "VAX" (little-endian) order
w                    A BER compressed unsigned integer in base 128, high bit first
x                    A null byte
X                    Back up a byte
@                    Null fill to absolute position