[ios::fmtflags]

using fmtflags = T1;

The type fmtflags is a bitmask type ([bitmask.types]). Setting its elements has the effects indicated in Table [tab:iostreams.fmtflags.effects].

Table 107 — fmtflags effects

Element	Effect(s) if set
boolalpha	insert and extract bool type in alphabetic format
dec	converts integer input or generates integer output in decimal base
fixed	generate floating-point output in fixed-point notation
hex	converts integer input or generates integer output in hexadecimal base
internal	adds fill characters at a designated internal point in certain generated output, or identical to right if no such point is designated
left	adds fill characters on the right (final positions) of certain generated output
oct	converts integer input or generates integer output in octal base
right	adds fill characters on the left (initial positions) of certain generated output
scientific	generates floating-point output in scientific notation
showbase	generates a prefix indicating the numeric base of generated integer output
showpoint	generates a decimal-point character unconditionally in generated floating-point output
showpos	generates a + sign in non-negative generated numeric output
skipws	skips leading whitespace before certain input operations
unitbuf	flushes output after each output operation
uppercase	replaces certain lowercase letters with their uppercase equivalents in generated output

Type fmtflags also defines the constants indicated in Table [tab:iostreams.fmtflags.constants].

Table 108 — fmtflags constants

27 Input/output library [input.output]