user-0 提问: C语言

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user: user-1
content: Collapse AllExpand All      Code: All Code: Multiple Code: Visual Basic Code: C# Code: Visual C++ Code: J# Code: JScript   Visual Basic C# Visual C++ J# JScript Run-Time Library Reference  printf_s, _printf_s_l, wprintf_s, _wprintf_s_l  Example  See Also  Send Feedback     Print formatted output to the standard output stream. These are versions of printf, _printf_l, wprintf, _wprintf_l with security enhancements as described in Security Enhancements in the CRT.    int printf_s(    const char *format [,       argument]...  ); int _printf_s_l(    const char *format,    locale_t locale [,       argument]...  ); int wprintf_s(    const wchar_t *format [,       argument]...  ); int _wprintf_s_l(    const wchar_t *format,    locale_t locale [,       argument]...  );    Parameters format Format control.  argument Optional arguments.  locale The locale to use.  Return Value Returns the number of characters printed, or a negative value if an error occurs.   Remarks The printf_s function formats and prints a series of characters and values to the standard output stream, stdout. If arguments follow the format string, the format string must contain specifications that determine the output format for the arguments.  The main difference between printf_s and printf is that printf_s checks the format string for valid formatting characters, whereas printf only checks if the format string is a null pointer. If either check fails, an invalid parameter handler is invoked, as described in Parameter Validation. If execution is allowed to continue, the function returns -1 and sets errno to EINVAL.  For information on errno and error codes, see _doserrno, errno, _sys_errlist, and _sys_nerr.  printf_sandfprintf_s behave identically except that printf_s writes output to stdout rather than to a destination of type FILE. For more information, see fprintf_s, _fprintf_s_l, fwprintf_s, _fwprintf_s_l.  wprintf_s is a wide-character version of printf_s; format is a wide-character string. wprintf_s and printf_s behave identically if the stream is opened in ANSI mode. printf_s doesn't currently support output into a UNICODE stream.   The versions of these functions with the _l suffix are identical except that they use the locale parameter passed in instead of the current thread locale.  TCHAR.H routine   _UNICODE & _MBCS not defined  _MBCS defined  _unicode defined   _tprintf_s  printf_s  printf_s  wprintf_s   _tprintf_s_l  _printf_s_l  _printf_s_l  _wprintf_s_l    The format argument consists of ordinary characters, escape sequences, and (if arguments follow format) format specifications. The ordinary characters and escape sequences are copied to stdout in order of their appearance. For example, the line    Copy Code  printf_s("Line one\n\t\tLine two\n");     produces the output    Copy Code  Line one         Line two    Format specifications always begin with a percent sign (%) and are read left to right. When printf_s encounters the first format specification (if any), it converts the value of the first argument after format and outputs it accordingly. The second format specification causes the second argument to be converted and output, and so on. If there are more arguments than there are format specifications, the extra arguments are ignored. The results are undefined if there are not enough arguments for all the format specifications.  Security Note:  Ensure that format is not a user-defined string.    Requirements Routine  Required header   printf_s, _printf_s_l  <stdio.h>   wprintf_s, _wprintf_s_l  <stdio.h> or <wchar.h>    For additional compatibility information, see Compatibility in the Introduction.  Example   Copy Code  // crt_printf_s.c /* This program uses the printf_s and wprintf_s functions  * to produce formatted output.  */  #include <stdio.h>  int main( void ) {    char   ch = 'h', *string = "computer";    int    count = -9234;    double fp = 251.7366;    wchar_t wch = L'w', *wstring = L"Unicode";     /* Display integers. */    printf_s( "Integer formats:\n"            "   Decimal: %d  Justified: %.6d  Unsigned: %u\n",            count, count, count, count );     printf_s( "Decimal %d as:\n   Hex: %Xh  C hex: 0x%x  Octal: %o\n",             count, count, count, count );     /* Display in different radixes. */    printf_s( "Digits 10 equal:\n   Hex: %i  Octal: %i  Decimal: %i\n",             0x10, 010, 10 );     /* Display characters. */     printf_s("Characters in field (1):\n%10c%5hc%5C%5lc\n", ch, ch, wch, wch);    wprintf_s(L"Characters in field (2):\n%10C%5hc%5c%5lc\n", ch, ch, wch, wch);     /* Display strings. */     printf_s("Strings in field (1):\n%25s\n%25.4hs\n   %S%25.3ls\n",    string, string, wstring, wstring);    wprintf_s(L"Strings in field (2):\n%25S\n%25.4hs\n   %s%25.3ls\n",        string, string, wstring, wstring);     /* Display real numbers. */    printf_s( "Real numbers:\n   %f %.2f %e %E\n", fp, fp, fp, fp );     /* Display pointer. */    printf_s( "\nAddress as:   %p\n", &count);  }    Sample Output   Copy Code  Integer formats:    Decimal: -9234  Justified: -009234  Unsigned: 4294958062 Decimal -9234 as:    Hex: FFFFDBEEh  C hex: 0xffffdbee  Octal: 37777755756 Digits 10 equal:    Hex: 16  Octal: 8  Decimal: 10 Characters in field (1):          h    h    w    w Characters in field (2):          h    h    w    w Strings in field (1):                  computer                      comp    Unicode                      Uni Strings in field (2):                  computer                      comp    Unicode                      Uni Real numbers:    251.736600 251.74 2.517366e+002 2.517366E+002  Address as:   0012FF78     .NET Framework Equivalent System::Console::Write  System::Console::WriteLine  See Also Concepts Floating-Point Support Stream I/O Locale fopen, _wfopen fprintf, _fprintf_l, fwprintf, _fwprintf_l scanf, _scanf_l, wscanf, _wscanf_l sprintf, _sprintf_l, swprintf, _swprintf_l, __swprintf_l vprintf Functions Send feedback on this topic to Microsoft.

user: user-2
content: printf_s有可能是自己声明的函数！ 你用whatis printf_s查询的话是没有的

user: user-3
content: 第二个比第一个多了一个_s

user: user-4
content: 没见过ptintf ，不过 printf 是标准库中的函数，printf_s是MSVC特有的