31 Input/output library [input.output]

31.5 Iostreams base classes [iostreams.base]

31.5.2 Class ios_base [ios.base]

31.5.2.2 Types [ios.types]

31.5.2.2.4 Type ios_base​::​openmode [ios.openmode]

Table 134 — openmode effects [tab:ios.openmode]
🔗
Element
Effect(s) if set
🔗
app
seek to end before each write
🔗
ate
open and seek to end immediately after opening
🔗
binary
perform input and output in binary mode (as opposed to text mode)
🔗
in
open for input
🔗
noreplace
open in exclusive mode
🔗
out
open for output
🔗
trunc
truncate an existing stream when opening