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g_write_data.9freebsd

BSD mandoc

NAME

g_read_data g_write_data - read/write data from/to GEOM consumer

SYNOPSIS

In geom/geom.h Ft void * Fo g_read_data Fa struct g_consumer *cp off_t offset off_t length int *error Fc Ft int Fo g_write_data Fa struct g_consumer *cp off_t offset void *ptr off_t length Fc  

DESCRIPTION

The Fn g_read_data function reads Fa length bytes of data from the provider attached to consumer Fa cp , starting at offset Fa offset . The buffer returned from Fn g_read_data is allocated with Fn g_malloc , so it should be freed by the caller with Fn g_free after use. If the operation fails, an error value will be stored in the Fa error argument if it is not NULL

The Fn g_write_data function writes Fa length bytes of data from the buffer pointed to by Fa ptr to the provider attached to consumer Fa cp , starting at offset Fa offset .

RESTRICTIONS/CONDITIONS

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

The topology lock must not be held.

RETURN VALUES

The Fn 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 Fa error argument unless it is NULL

The Fn g_write_data function returns 0 if successful; otherwise an error code is returned.

ERRORS

Possible errors:

Bq Er EIO

An I/O error occurred while reading from or writing to the consumer.

SEE ALSO

geom(4), DECLARE_GEOM_CLASS9, g_access9, g_attach9, g_bio9, g_consumer9, g_event9, g_geom9, g_provider9, g_provider_by_name9, g_wither_geom9

AUTHORS

An -nosplit This manual page was written by An Pawel Jakub Dawidek Aq pjd@FreeBSD.org .