Entries tagged as Unix
function of “errno”
What function does “errno” do?
Sometimes it is nice to know what specific error occurred; for this purpose all system calls, when appropriate, leave an error number in an external integer called calls, when appropriate, leave an error number in an external integer called errno. By using errno, your program can, for example, determine whether an Read More...
Read slow
Explain about read slow.
One can call to read return 0 which signals the end of file life, if data is written on that file then a subsequent read will be able to find more bytes available. This observation is the basis of a program called readslow which continues to read its input, regardless of whether Read More...
Special arrangements to make a terminal i/p and o/p
What are the special arrangements to make a terminal i/p and o/p?
When it is started by the shell, a program inherits three open files, with file descriptor 0, 1 and 2 called the standard i/p, the standard o/p, and the standard error. If the program reads “0” and writes descriptors 1 and 2, it can Read More...
Low-level I/O
Explain about low-level I/O.
The lowest of I/O is a direct entry into the O.S. your program reads or writes files in chunks of any convenient size. The kernel buffers your data into chunks that match the peripheral devices and schedule operations on the devices to optimize their performance over all users.
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