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Function std.format.sformat
Converts its arguments according to a format string into a buffer. The buffer has to be large enough to hold the formatted string.
char[] sformat(Char, Args...)
(
scope return char[] buf,
scope const(Char)[] fmt,
Args args
);
char[] sformat(alias fmt, Args...)
(
char[] buf,
Args args
)
if (isSomeString!(typeof(fmt)));
The second version of sformat
takes the format string as a template
argument. In this case, it is checked for consistency at
compile-time.
Parameters
Name | Description |
---|---|
buf | the buffer where the formatted string should go |
fmt | a format string |
args | a variadic list of arguments to be formatted |
Char | character type of fmt |
Args | a variadic list of types of the arguments |
Returns
A slice of buf
containing the formatted string.
Throws
A RangeError if buf
isn't large enough to hold the formatted string
and a FormatException
if formatting did not succeed.
Note
In theory this function should be @nogc
. But with the current
implementation there are some cases where allocations occur:
- An exception is thrown.
- A custom
toString
function of a compound type allocates.
Example
char[20] buf;
writeln(sformat(buf[], "Here are %d %s.", 3, "apples")); // "Here are 3 apples."
writeln(buf[] .sformat("Increase: %7.2f %%", 17.4285)); // "Increase: 17.43 %"
Example
The format string can be checked at compile-time:
char[20] buf;
writeln(sformat!"Here are %d %s."(buf[], 3, "apples")); // "Here are 3 apples."
// This line doesn't compile, because 3.14 cannot be formatted with %d:
// writeln(sformat!"Here are %d %s."(buf[], 3.14, "apples"));
Authors
Walter Bright, Andrei Alexandrescu, and Kenji Hara
License
Copyright © 1999-2022 by the D Language Foundation | Page generated by ddox.