NAME

vwrite − write (virtually) to file

SYNOPSIS

vwrite(filedes, buffer, nbytes)
char ∗buffer;

DESCRIPTION

The vwrite system call is used in conjunction with vread to perform efficient updating of large files.  After a call to vread and updating of the data in the buffer which was given to vread, a vwrite of the same buffer to the same filedes at the same offset in the file will cause data which has been modified since it was vread from (or vwritten to) the file to be returned to the file. 

SEE ALSO

vread(2)

DIAGNOSTICS

Returns −1 on error: bad descriptor, buffer address, count or alignment as well as on physical I/O errors. 

BUGS

The result of vwrite is defined only when no other vread’s have occured on buffer since the one matching the vwrite. 

3rd Berkeley Distribution