C-Style Format Strings¶
Some types can be serialized/deserialized to/from messages using C-style
format strings. In C-style format strings, placeholders beginning with the
% character indicate locations in the string that map to variables of
the designated type. These placeholders take the form of:
%[flags][width][.precision][length]type
where the fields are:
| Field | Description |
|---|---|
| flags | Flags indicating if the string representation should be padded to the designated with and, if so, should the string be left or right justified in the space. |
| width | Minimum width that the corresponding string representation of the variable should occupy in characters. |
| precision | Limit on the maximum width that the string representation should occupy based on the type of the variable. |
| length | Character code indicating the size of the variable expected. |
| type | Character code specifying what type the placeholder represents. This is the only required field. |
These strings can then be used to create messages from a list of variables
(printf) or extract variable from messages (scanf).
Some of the most common types are:
| Type Code | Type |
|---|---|
s |
String |
d |
Integer |
f |
Float |
e or E |
Exponential notation float with e or E denoting the
exponent. |
g or G |
General format that uses %f for numbers with small
exponents and %e or %E for numbers with large
exponents. |
For additional information about available types or how the fields are used for each type, please see the help for C’s printf function.