sd_card_open_read_close()

int sd_card_open_read_close	(	char const *const	filename,
		char *const	buf,
		size_t *	size )

Read data from file into the buffer.

Parameters

[in]	filename	Name of the target file for reading, the default location is the root directoy of SD card, accept absolute path under root of SD card.
[out]	buf	Pointer to the buffer to write the read data into.
[in,out]	size	Pointer to the number of bytes which wait to be read from the file. The actual read size will be returned. If the actual read size is 0, there will be a warning message which indicates that the file is empty.

Return values

0	on success.
-EPERM	SD card operation is ongoing somewhere else.
-ENODEV	SD init failed. SD card likely not inserted.
Otherwise,error	from underlying drivers.