table of contents
|G_DATA(9)||Kernel Developer's Manual||G_DATA(9)|
NAME¶g_read_data, g_write_data — read/write data from/to GEOM consumer
SYNOPSIS¶#include <geom/geom.h> void *
g_read_data(struct g_consumer *cp, off_t offset, off_t length, int *error); int
g_write_data(struct g_consumer *cp, off_t offset, void *ptr, off_t length);
DESCRIPTION¶The g_read_data() function reads length bytes of data from the provider attached to consumer cp, starting at offset offset. The buffer returned from g_read_data() is allocated with g_malloc(), so it should be freed by the caller with g_free() after use. If the operation fails, an error value will be stored in the error argument if it is not
NULL. The g_write_data() function writes length bytes of data from the buffer pointed to by ptr to the provider attached to consumer cp, starting at offset offset.
RESTRICTIONS/CONDITIONS¶The length argument should be a multiple of the provider's sectorsize and less than or equal to
DFLTPHYSis defined in <sys/param.h>). The topology lock must not be held.
RETURN VALUES¶The g_read_data() function returns a pointer to a data buffer or
NULLif an error occurred. In that case an error value is stored in the error argument unless it is
NULL. The g_write_data() function returns 0 if successful; otherwise an error code is returned.
- An I/O error occurred while reading from or writing to the consumer.
SEE ALSO¶geom(4), DECLARE_GEOM_CLASS(9), g_access(9), g_attach(9), g_bio(9), g_consumer(9), g_event(9), g_geom(9), g_provider(9), g_provider_by_name(9), g_wither_geom(9)
AUTHORS¶This manual page was written by Pawel Jakub Dawidek ⟨pjd@FreeBSD.org⟩.
|January 16, 2004||Debian|