Provided by: libvrb0-dev_0.5.1-5.1_amd64
vrb_read_min - read a minimum of data into a VRB
#include <vrb.h> size_t vrb_read_min(vrb_p vrb, int fd, size_t maxsize, size_t minsize);
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.
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.
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).
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.
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)