WRITE(2) WRITE(2)
NAME
write - write on a file
SYNOPSIS
write(fildes, buffer, nbytes)
char *buffer;
DESCRIPTION
Write writes data on the open file associated with the file
descriptor.
Buffer is the address of nbytes contiguous bytes which are
written on the output file. The number of characters actu-
ally written is returned. It should be regarded as an error
if this is not the same as requested.
If the open file is being read by another process, data of
at most one write will be delivered to any read(2) in the
other process. In particular, if nbytes = 0, the read will
return a count of 0, which is conventionally taken to mean
end of file.
Writes which are synchronized with file system blocks are
more efficient than others; see filsys(5).
On some systems write clears the set-user-id bit on a file.
This prevents penetration of system security by a user who
captures a writable set-user-id file that he does not own.
SEE ALSO
creat(2), open(2), pipe(2), select(2)
DIAGNOSTICS
Returns -1 on error: bad descriptor, buffer address, or
count; physical I/O errors.