sprintf_s, swprintf_s
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Header File
stdio.h
Category
Formatted input/output functions
Prototype
int sprintf_s(char * restrict s, rsize_t n, const char * restrict format, ...);
int swprintf_s(wchar_t * restrict s, rsize_t n, const wchar_t * restrict format, ...);
Description
Replaces sprintf adding security enhancements.
sprintf_s is equivalent to sprintf, except for the run-time constraint that restricts s and format from being null pointers. Other constraints require that every format specifier in format that is %s have respective non-null arguments and the %n specifier not be used in format.
If a run-time constraint violation occurs, s is not a null pointer, and n is greater than zero and less than RSIZE_MAX, then the function puts '\0' to s[0].
Unlike snprintf_s, snwprintf_s, in case n is bigger than the array that is pointed to by s, it raises a run-time constraint exception.
Return Value
On success, sprintf_s returns the number of characters output, not including the terminal '\0'. In case of an encoding error, sprintf_s returns a negative value. Any other error case returns zero.
Example
#include <stdio.h>
#include <math.h>
int main(void)
{
char buffer[80];
sprintf_s(buffer, 40, "An approximation of Pi is %f\n", M_PI);
puts(buffer);
return 0;
}
Portability
| POSIX | Win32 | ANSI C | ANSI C++ | |
|---|---|---|---|---|
|
sprintf_s |
+ |
+ |
+ |
+ |
|
swprintf_s |
+ |
+ |
+ |