strlcat function

C

Function

Reference manual

@see man strlcat

The strlcat function appends the content of one string src to another string dst while ensuring that the resulting string is null-terminated and does not exceed a specified buffer size. It returns the total length of the resulting string.

Syntax

size_t strlcat(char *dst, const char *src, size_t size);

Parameters

• dst: The destination string to which the content of src is appended.
• src: The source string to be appended to dst.
• size: The size of the buffer (including the null-terminator) to prevent buffer overflows.

Return value

Returns the total length of the resulting string after concatenation. If the buffer size is insufficient to accommodate the entire result, it returns the required buffer size.

Example

In the following example we use the strlcat function to append the string “World!” to the string “Hello, “ and then we output the resulting string “Hello, World!” and its length.

#include <stdio.h>
#include <string.h>

int main(void)
{
    char destination[20] = "Hello, ";
    const char *source = "World!";
    size_t total_length;

    total_length = strlcat(destination, source, sizeof(destination));
    printf("Concatenated string: %s\n", destination);
    printf("Total length: %zu\n", total_length);
    return (0);
}