/usr/lib/grass70/include/grass/rowio.h is in grass-dev 7.0.3-1build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 | #ifndef GRASS_ROWIO_H
#define GRASS_ROWIO_H
typedef struct
{
    int fd;			/* file descriptor for reading */
    int nrows;			/* number of rows to be held in memory */
    int len;			/* buffer length */
    int cur;			/* current row in memory */
    void *buf;			/* current data buf */
    int (*getrow) (int, void *, int, int);	/* routine to do the row reads */
    int (*putrow) (int, const void *, int, int);	/* routine to do the row writes */
    struct ROWIO_RCB
    {
	void *buf;		/* data buffer */
	int age;		/* for order of access */
	int row;		/* row number */
	int dirty;
    } *rcb;
} ROWIO;
#include <grass/defs/rowio.h>
#endif
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