HP 3000 Manuals HP 3000 Manuals
read
Reads input from a file.
Syntax
int read (int fildes, char *buffer, unsigned nbyte);
Parameters
fildes An open file descriptor.
buffer A pointer to a buffer where the function returns data.
nbyte The number of bytes to read and place in buffer.
Return Values
>0 Indicates success and the number of bytes read. This
number may be less than nbyte if:
* The file is associated with a communication line.
* The number of bytes left in the file is less than
nbyte bytes.
EOF Returned when an end-of-file is reached.
-1 Indicates unsuccessful completion. The errno variable is
set if one of the following conditions is true:
EBADF The fildes parameter is not a valid file
descriptor open for reading.
ESYSERR A call to a system intrinsic failed.
Description
The read function reads nbyte bytes from the file associated with fildes
and places the data read into the buffer pointed to by buffer.
On devices capable of seeking, read() starts at a position in the file
given by the file offset associated with fildes. Upon return from
read(), the file pointer is incremented by the number of bytes actually
read.
Devices that are incapable of seeking always read from the current
position. The value of a file offset associated with such a device is
undefined.
Unless an error occurs, a process blocks until a read() request is
completed.
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NOTE If linking with the POSIX/iX library, refer to the description of
read() located in the MPE/iX Developer's Kit Reference Manual.
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See Also
open(), write()