I have an existing
and working code that uses the proc file system.
One of the functions
in the code, foo_write, is being called whenever something
is written into my
file in the proc.
My
observations are as follows:
- The
return code of foo_write affects the original "write" that wrote to the
file
- If
foo_write returns a positive X, the "write" returns with X, and errno is
0
- If
foo_write returns a negative X, the "write" returns -1, and errno is set to -X
(i.e. a positive value)
- If
foo_write returns a zero... I am not sure.
Is this
correct ?
What
happens with a zero value ?
Where can
I find more information ?
Side issue: if I
"write" using "echo" in a shell script, is there any way to access errno
?
TIA
