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vrb_read_min

vrb_read_min

Section: VRB Programmer's Manual (3) Updated: 2002-09-30
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NAME

vrb_read_min - read a minimum of data into a VRB  

LIBRARY

-lvrb  

SYNOPSIS

#include <vrb.h>

size_t vrb_read_min(vrb_p vrb, int fd, size_t maxsize, size_t minsize);  

DESCRIPTION

vrb_read_min reads a minimum amount of data from a specified open file descriptor using read(2) into the specified virtual ring buffer until the specified maximum length has been read, the buffer is full, or end-of-file, or an error is returned (including EAGAIN or EWOULDBLOCK for a non-blocking descriptor). If there is insufficient space in the buffer to read the minimum amount, then read(2) will not be called.  

ARGUMENTS

vrb_p vrb
specifies which virtual ring buffer.

int fd
specifies the open file descriptor to read from

size_t maxsize
specifies the maximum length to read, or ~0 for unlimited.

size_t minsize
specifies the minimum length to read.  

RETURN VALUE

size_t
If successful, the actual length of data read into the buffer is returned. If the minimum amount of space was not available to read into, 0 is returned. If end-of-file occurs, the return value is ~0 and errno is 0. If an error occurs from read(2), the return value is ~0 and errno is set by read(2).  

ERRORS

If an error is returned, then errno will have one of the following values:
0
An end-of-file has occurred. Note that this is a different way of returning an end-of-file condition than read(2) uses.
EINVAL
An invalid virtual ring buffer pointer was specified.
 

SEE ALSO

vrb(3), vrb_capacity(3), vrb_data_len(3), vrb_data_ptr(3), vrb_destroy(3), vrb_get(3), vrb_get_min(3), vrb_give(3), vrb_init(3), vrb_init_opt(3), vrb_is_empty(3), vrb_is_full(3), vrb_is_not_empty(3), vrb_is_not_full(3), vrb_move(3), vrb_new(3), vrb_new_opt(3), vrb_put(3), vrb_put_all(3), vrb_read(3), vrb_resize(3), vrb_space_len(3), vrb_space_ptr(3), vrb_take(3), vrb_uninit(3), vrb_write(3), vrb_write_min(3), read(2)


 

Index

NAME
LIBRARY
SYNOPSIS
DESCRIPTION
ARGUMENTS
RETURN VALUE
ERRORS
SEE ALSO

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Time: 21:58:09 GMT, April 16, 2011