Question

snprintf in a loop does not work on linux but it works properly on windows.

#include <stdio.h>
#include <stdlib.h>

    int main( int argc, char **argv) {
      char buffer[255] ={0};
      for ( int i = 0; i < 10; i++) {
        snprintf(buffer, 255, "%s:%x\0",buffer,  i );
      }
      printf ( "BUFFER  = %s\n", buffer );
      return 0;
    }

This code does not append existing buffer but only takes the last iteration value.

Answer 1

You can avoid the undefined behavior of using the buffer both as the target string and as an argument like this:

#include <stdio.h>
#include <stdlib.h>

int main( int argc, char **argv) {
  char buffer[255] ={0};
  int offset = 0;
  for ( int i = 0; i < 10; i++) {
    offset += snprintf(buffer + offset, 255 - offset, ":%x\0", i);
  }
  printf ( "BUFFER  = %s\n", buffer );
  return 0;
}