---
name: "ts_read"
section: "3"
platform: "linux"
package: "tslib"
version: "1.24-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/ts_read"
---

# ts\_read(3)

read tslib touch samples

## NAME

ts\_read, ts\_read\_raw, ts\_read\_mt, ts\_read\_raw\_mt - read tslib touch samples

## SYNOPSIS

```
#include <tslib.h>

int ts_read(struct tsdev *dev, struct ts_sample *samp, int nr);

int ts_read_raw(struct tsdev *dev, struct ts_sample *samp, int nr);

int ts_read_mt(struct tsdev *dev, struct ts_sample_mt **samp, int slots, int nr);

int ts_read_raw_mt(struct tsdev *dev, struct ts_sample_mt **samp, int slots, int nr);

```

## DESCRIPTION

**ts\_read**() reads **nr** input samples with tslib's filters applied. **struct ts\_sample** is define as follows:

```
struct ts_sample {
        int             x;
        int             y;
        unsigned int    pressure;
        struct timeval  tv;
};
```

**ts\_read\_mt()** reads **nr** \* **slots** input samples with tslib's filters applied. **struct ts\_sample\_mt** is defined as follows:

```
struct ts_sample_mt {
        /* most recent ABS_MT_* event codes.
         * see linux/input.h for descriptions */
        int             x;
        int             y;
        unsigned int    pressure;
        int             slot;
        int             tracking_id;
        int             tool_type;
        int             tool_x;
        int             tool_y;
        unsigned int    touch_major;
        unsigned int    width_major;
        unsigned int    touch_minor;
        unsigned int    width_minor;
        int             orientation;
        int             distance;
        int             blob_id;
        struct timeval  tv;
        /* BTN_TOUCH state */
        short           pen_down;
        /* the TSLIB_MT_VALID bit is set in valid if this sample
         * contains new data;
	 * valid is set to 0 otherwise */
        short           valid;
};
```

The user has to provide the amount of memory described in **nr** and **slots** to hold them.

**ts\_read\_raw**() and **ts\_read\_raw\_mt**() do the same thing without tslib's filters applied.

## RETURN VALUE

The number of actually read samples is returned. Especially when opened in non-blocking mode, see **ts\_setup()** , that can be less than requested in the call. On failure, a negative error number is returned.

## EXAMPLE

The following program continuously reads tslib multitouch input samples and prints slot and position values to stdout as the touch screen is touched.

```
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <tslib.h>
#define READ_SAMPLES 1
#define MAX_SLOTS 5
int main(int argc, char **argv)
{
        struct tsdev *ts;
        struct ts_sample_mt **samp_mt = NULL;
        int i, j;
        int ret;
        ts = ts_setup(NULL, 0);
        if (!ts)
                return -1;
        samp_mt = malloc(READ_SAMPLES * sizeof(struct ts_sample_mt **));
        if (!samp_mt)
                return -1;
        for (i = 0; i < READ_SAMPLES; i++) {
                samp_mt[i] = calloc(MAX_SLOTS, sizeof(struct ts_sample_mt));
                if (!samp_mt[i])
                        return -1;
        }
        while(1) {
                ret = ts_read_mt(ts, samp_mt, MAX_SLOTS, READ_SAMPLES);
                for (i = 0; i < ret; i++) {
                        printf("sample nr %d0, i);
                        for (j = 0; i < MAX_SLOTS; j++) {
                                if (!(samp_mt[i][j].valid & TSLIB_MT_VALID))
                                        continue;
                                printf("slot %d: X:%d Y: %d0,
                                       samp_mt[i][j].slot,
                                       samp_mt[i][j].x,
                                       samp_mt[i][j].y);
                        }
                }
        }
}
```

## SEE ALSO

[**ts\_setup**(3)](/ts_setup/3.md), [**ts\_config**(3)](/ts_config/3.md), [**ts\_open**(3)](/ts_open/3.md), [**ts\_close**(3)](/ts_close/3.md), [**ts.conf**(5)](/ts.conf/5.md)