Manual Pages  — G_DATA

g_read_data, g_write_data – read/write data from/to GEOM consumer

SYNOPSIS DESCRIPTION RESTRICTIONS/CONDITIONS RETURN VALUES ERRORS SEE ALSO AUTHORS

#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);

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.

The length argument should be a multiple of the provider's sectorsize and less than or equal to DFLTPHYS ( DFLTPHYS is defined in <sys/param.h>).

The topology lock must not be held.

The g_read_data() function returns a pointer to a data buffer or NULL if 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.

Possible errors:

[EIO]	An I/O error occurred while reading from or writing to the consumer.
[EINTEGRITY]
	Corrupted data was detected while reading from the consumer.

This manual page was written by Pawel Jakub Dawidek <Mt pjd@FreeBSD.org>.