[ios.fmtflags] # 31 Input/output library [[input.output]](./#input.output) ## 31.5 Iostreams base classes [[iostreams.base]](iostreams.base#ios.fmtflags) ### 31.5.2 Class ios_base [[ios.base]](ios.base#ios.fmtflags) #### 31.5.2.2 Types [[ios.types]](ios.types#ios.fmtflags) #### 31.5.2.2.2 Type ios_base​::​fmtflags [ios.fmtflags] [🔗](#lib:fmtflags,ios_base) `using fmtflags = T1; ` [1](#1) [#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L976) The typefmtflags is a bitmask type ([[bitmask.types]](bitmask.types "16.3.3.3.3 Bitmask types"))[.](#1.sentence-1) Setting its elements has the effects indicated in Table [136](#tab:ios.fmtflags "Table 136: fmtflags effects")[.](#1.sentence-2) Table [136](#tab:ios.fmtflags) — fmtflags effects [[tab:ios.fmtflags]](./tab:ios.fmtflags) | [🔗](#tab:ios.fmtflags-row-1)
**Element** | **Effect(s) if set** | | --- | --- | | [🔗](#tab:ios.fmtflags-row-2)
boolalpha | insert and extract bool type in alphabetic format | | [🔗](#tab:ios.fmtflags-row-3)
dec | converts integer input or generates integer output in decimal base | | [🔗](#tab:ios.fmtflags-row-4)
fixed | generate floating-point output in fixed-point notation | | [🔗](#tab:ios.fmtflags-row-5)
hex | converts integer input or generates integer output in hexadecimal base | | [🔗](#tab:ios.fmtflags-row-6)
internal | adds fill characters at a designated internal point in certain generated output, or identical to right if no such point is designated | | [🔗](#tab:ios.fmtflags-row-7)
left | adds fill characters on the right (final positions) of certain generated output | | [🔗](#tab:ios.fmtflags-row-8)
oct | converts integer input or generates integer output in octal base | | [🔗](#tab:ios.fmtflags-row-9)
right | adds fill characters on the left (initial positions) of certain generated output | | [🔗](#tab:ios.fmtflags-row-10)
scientific | generates floating-point output in scientific notation | | [🔗](#tab:ios.fmtflags-row-11)
showbase | generates a prefix indicating the numeric base of generated integer output | | [🔗](#tab:ios.fmtflags-row-12)
showpoint | generates a decimal-point character unconditionally in generated floating-point output | | [🔗](#tab:ios.fmtflags-row-13)
showpos | generates a + sign in non-negative generated numeric output | | [🔗](#tab:ios.fmtflags-row-14)
skipws | skips leading whitespace before certain input operations | | [🔗](#tab:ios.fmtflags-row-15)
unitbuf | flushes output after each output operation | | [🔗](#tab:ios.fmtflags-row-16)
uppercase | replaces certain lowercase letters with their uppercase equivalents in generated output | [2](#2) [#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L1016) Typefmtflags also defines the constants indicated in Table [137](#tab:ios.fmtflags.const "Table 137: fmtflags constants")[.](#2.sentence-1) Table [137](#tab:ios.fmtflags.const) — fmtflags constants [[tab:ios.fmtflags.const]](./tab:ios.fmtflags.const) | [🔗](#tab:ios.fmtflags.const-row-1)
**Constant** | **Allowable values** | | --- | --- | | [🔗](#tab:ios.fmtflags.const-row-2)
adjustfield | left | right | internal | | [🔗](#tab:ios.fmtflags.const-row-3)
basefield | dec | oct | hex | | [🔗](#tab:ios.fmtflags.const-row-4)
floatfield | scientific | fixed |