about 3rd param for uv.fs_write

[zhaozg]

Think about this

uv.fs_write(dev,chunk,0)
uv.fs_write(dev,chunk,0,cb)

3rd param meas offset in string, If it is optional val, will make code clear.
after have this feature, just change to

uv.fs_write(dev,chunk)
uv.fs_write(dev,chunk,cb)

[creationix]

luv is meant to be fairly low-level and not have much sugar like optional parameters. The wrapping in luvit does make it optional. https://github.com/luvit/luvit/blob/c274290954c5b23eccdac3fcabaf575dc2f2c633/app/modules/fs.lua#L142-L160

Also according to the man page for pwritev(2) (which is all the libuv docs for uv_fs_write mention), offset is the offset in the file being written to, not an offset in the source buffer.

The pwritev() system call combines the functionality of writev() and pwrite(2). It performs the same task as writev(), but adds a fourth argument, offset, which specifies the file offset at which the output operation is to be performed.

[zhaozg]

Got it, thinks