snprintf function Usage

Function prototypes

int snprintf (char *str, size_t size, const char *format, ...)

Function

A variable parameter (...) Formats the string as format and then copies it to Str

(1) If the string length < size is formatted, copy the string to str and add a string terminator (' + ') to it;

(2) If the formatted string length >= size, only the (size-1) characters are copied to STR, followed by a string terminator (' + '), and the return value is the length of the string to be written.

return value

Returns the length of the string to be written if successful, or a negative value If an error occurs.

Description

strcpy () sprintf () strcat () has security implications, no cross-border checks, and its corresponding security version is:

strncpy () snprintf () Strncat ()

As an example,

#include <stdio.h> #include <stdlib.h>int main () {char str[10]={0};  int nlen=snprintf (str,sizeof (str), "0123456789012345678");  printf ("str=%s\n", str);  printf ("nlen=%d\n", Nlen); return 0;}

Run results

snprintf function Usage