C / C++中的wcrtomb()函数将宽字符转换为其窄的多字节表示形式。宽字符wc转换为其等效的多字节,并存储在s指向的数组中。该函数返回s指向的等效多字节序列的长度(以字节为单位) 。
句法 :
size_t wcrtomb( char* s, wchar_t wc, mbstate_t* ps )
参数:该函数接受三个强制性参数,如下所述:
- s:指定指向足以容纳多字节序列的数组的指针
- wc:指定要转换的宽字符。
- ps:指定在解释多字节字符串时使用的转换状态的指针
返回值:该函数返回两个值,如下所示:
- 成功后,它将返回写入字符数组的字节数,该字符数组的第一个元素由s指向。
- 否则,它返回-1并将errno设置为EILSEQ 。
下面的程序说明了上述函数:
程序1:
// C++ program to illustrate the
// wcrtomb() function
#include
using namespace std;
int main()
{
setlocale(LC_ALL, "en_US.utf8");
// initialize the string
wchar_t wc[] = L"z\u00df\u6c34\U0001f34c";
// array large enough to hold a multibyte sequence
char s[25];
int returnV;
// initial state
mbstate_t ps = mbstate_t();
for (int i = 0; i < wcslen(wc); i++) {
returnV = wcrtomb(s, wc[i], &ps);
// print byte size, if its a valid character
if (returnV != -1)
cout << "Size of " << s << " is "
<< returnV << " bytes" << endl;
else
cout << "Invalid wide character" << endl;
}
return 0;
}
输出:
Size of z is 1 bytes
Size of Ã? is 2 bytes
Size of æ°´ is 3 bytes
Size of ð?? is 4 bytes
程序2:
// C++ program to illustrate the
// wcrtomb() function
#include
using namespace std;
int main()
{
setlocale(LC_ALL, "en_US.utf8");
// initialize the string
wchar_t wc[] = L"u\u00c6\u00f5\u01b5";
// array large enough to hold a multibyte sequence
char s[20];
int returnV;
// initial state
mbstate_t ps = mbstate_t();
for (int i = 0; i < wcslen(wc); i++) {
returnV = wcrtomb(s, wc[i], &ps);
// print byte size, if its a valid character
if (returnV != -1)
cout << "Size of " << s << " is "
<< returnV << " bytes" << endl;
else
cout << "Invalid wide character" << endl;
}
return 0;
}
输出:
Size of u Ì_e is 1 bytes
Size of Ã?Ì_e is 2 bytes
Size of õÌ_e is 2 bytes
Size of ƵÌ_e is 2 bytes
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