Variable: write-region-inhibit-fsync
write-region-inhibit-fsync is a variable defined in fileio.c.
Value
t
Documentation
Non-nil means don't call fsync in write-region.
This variable affects calls to write-region as well as save commands.
By default, it is non-nil.
Although setting this to nil may avoid data loss if the system loses power, it can be a significant performance hit in the usual case, and it doesn't necessarily cause file-save operations to actually survive a crash.
Probably introduced at or before Emacs version 22.1.
Source Code
// Defined in /usr/src/emacs/src/fileio.c
DEFVAR_BOOL ("write-region-inhibit-fsync", write_region_inhibit_fsync,
doc: /* Non-nil means don't call fsync in `write-region'.
This variable affects calls to `write-region' as well as save commands.
By default, it is non-nil.
Although setting this to nil may avoid data loss if the system loses power,
it can be a significant performance hit in the usual case, and it doesn't
necessarily cause file-save operations to actually survive a crash. */);