Writing to file with Offset. How?

[SeeD]

Is there any way to write files with offset?
For example, I need to write value 01 in #2C5C

All I found was fileSeek function, but it`s not what I am looking for.

Sorry for my bad English and thanks in advance!

[ooPo]

http://luanet.net/lua/function/seek

function file:seek ( whence, offset )

Looks to me like you can do:

Code: Select all

file:seek("set", 0x2C5C)
file:write(0x01)

That doesn't work for you?

[SeeD]

thank you for helping =)

here is my code

Code: Select all

file = io.open("test", "wb")
file:seek("set", 0x03) 
file:write(0x01)

file:close()

test file before writing (HEX):

00 00 00 00 00 00 00

test file after LUA (HEX):
00 00 00 31

what should I use as an instance of file:write?
thanks again!

[romero126]

Use options "+r"

[PeterM]

Just to clarify, you're using "wb" which opens a new file (deletes the old one) in binary mode.