diff options
Diffstat (limited to 'src/fmt/doc.go')
| -rw-r--r-- | src/fmt/doc.go | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/src/fmt/doc.go b/src/fmt/doc.go index 5af8d3e71..00dd8d01c 100644 --- a/src/fmt/doc.go +++ b/src/fmt/doc.go @@ -63,16 +63,20 @@ %9.2f width 9, precision 2 %9.f width 9, precision 0 - Width and precision are measured in units of Unicode code points. - (This differs from C's printf where the units are numbers - of bytes.) Either or both of the flags may be replaced with the - character '*', causing their values to be obtained from the next - operand, which must be of type int. + Width and precision are measured in units of Unicode code points, + that is, runes. (This differs from C's printf where the + units are always measured in bytes.) Either or both of the flags + may be replaced with the character '*', causing their values to be + obtained from the next operand, which must be of type int. - For most values, width is the minimum number of characters to output, + For most values, width is the minimum number of runes to output, padding the formatted form with spaces if necessary. - For strings, precision is the maximum number of characters to output, - truncating if necessary. + + For strings, byte slices and byte arrays, however, precision + limits the length of the input to be formatted (not the size of + the output), truncating if necessary. Normally it is measured in + runes, but for these types when formatted with the %x or %X format + it is measured in bytes. For floating-point values, width sets the minimum width of the field and precision sets the number of places after the decimal, if appropriate, @@ -147,6 +151,10 @@ func (x X) String() string { return Sprintf("<%s>", x) } convert the value before recurring: func (x X) String() string { return Sprintf("<%s>", string(x)) } + Infinite recursion can also be triggered by self-referential data + structures, such as a slice that contains itself as an element, if + that type has a String method. Such pathologies are rare, however, + and the package does not protect against them. Explicit argument indexes: |