function::user_int16 - Linux


The user_int16 function is used to calculate the 16-bit checksum of a user-supplied buffer. This checksum can be used to verify the integrity of data during transmission or storage.


uint16_t user_int16(void *buf, size_t buflen);


| Parameter | Description |
| buf | Pointer to the buffer containing the data to checksum |
| buflen | Length of the buffer in bytes |

Return Value

The user_int16 function returns a 16-bit checksum of the data in the buffer. The checksum is calculated by summing the 16-bit words in the buffer and then taking the one’s complement of the sum.


The user_int16 function does not support any options or flags.


The following example shows how to calculate the checksum of a buffer of data:

#include <stdio.h>
#include <stdlib.h>

int main()
    uint8_t buf[] = { 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88 };
    size_t buflen = sizeof(buf);
    uint16_t checksum;

    checksum = user_int16(buf, buflen);

    printf("Checksum: 0x%04x\n", checksum);

    return 0;

The output of the program is:

Checksum: 0xc6d7

Common Issues

One common issue that users may encounter when using the user_int16 function is that the checksum is not correct. This can be caused by a number of factors, such as:

  • The data in the buffer is corrupted.
  • The buffer length is incorrect.
  • The checksum algorithm is not implemented correctly.


The user_int16 function can be used with other Linux commands and tools to perform a variety of tasks. For example, it can be used to:

  • Verify the integrity of data that is stored on a disk or other storage device.
  • Check for errors in data that is transmitted over a network.
  • Create a checksum of a file or directory for later verification.

Related Commands

The following commands are related to the user_int16 function:

  • user_int32: Calculates a 32-bit checksum of a user-supplied buffer.
  • user_crc32: Calculates a 32-bit CRC-32 checksum of a user-supplied buffer.
  • md5sum: Calculates an MD5 checksum of a file or directory.
  • sha1sum: Calculates an SHA-1 checksum of a file or directory.