| WCSLCAT(3C) | Standard C Library Functions | WCSLCAT(3C) |
wcslcat —
concatenate wide-character strings
Standard C Library (libc, -lc)
#include
<wchar.h>
size_t
wcslcat(wchar_t *restrict dst,
wchar_t *restrict src, size_t
dstlen);
The
wcslcat()
function is the wide-character version of
strlcat(3C). It concatenates the
wide-character string in src with the wide-character
string in dst, while ensuring that
dst is always properly terminated with the null
wide-character (L'\0').
Wide characters in src will be appended to dst starting at the end of an existing wide-character string in dst, replacing an existing terminating null wide-character. Put differently, copying will begin at the result of a call to the equivalent of wcsnlen(dst, dstlen). Characters will be copied until either a terminating null wide-character is found in src or the destination buffer would be full, whichever comes first. This may result in a truncated portion of src, or none at all, appearing in dst.
A terminating null wide-character is inserted unless the initial wide-character string in dst contained dstlen characters without a terminating null wide-character. However, if dstlen is zero, then dst will not be touched.
The wcslcat() function returns the total
number of wide characters that would be required to store the concatenated
wide-character string, excluding the terminating null wide-character.
Example 1 Checking for overflow
The following example shows how one would check if string
concatenation with the wcslcat() function resulted
in overflow. Note, the use of ‘>=’ down below is required
because the wcslcat() function always ensures that
the buffer has a terminating null wide-character.
#include <wchar.h>
#include <err.h>
#include <stdlib.h>
#define BUFLEN 32
wchar_t buf[BUFLEN] = { L'\0' };
...
static void
concat(const wchar_t *src)
{
if (wcslcat(buf, src, BUFLEN) >= BUFLEN) {
errx(EXIT_FAILURE, "overflow detected!");
}
}
...
| January 5, 2025 | OmniOS |