13.7: File Write
- Page ID
- 58403
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The arguments for the file write system service are as follows:
|
Register |
SYS_write |
|
rax |
Call code = SYS_write (1) |
|
rdi |
File descriptor (of open file) |
|
rsi |
Address of characters to write |
|
rdx |
Count of characters to write |
Assuming the following declarations:
SYS_write equ 1 ; file write
If the file write operation does not succeed, a negative value is returned in the rax register. If the file write operation does succeed, the number of characters actually written is returned.
Refer to the section on Example File Read for a compete file write example.