Concat wchar_t Unicode strings in C?

I'm a beginner, I play with FindFirstFileW() of the winapi - C. The unicoded path is: " \\?\c:\Français\", and I would 开发者_Python百科like to concat "*" to this path of type wchar_t (then I will use it as an arg for FindFirstFileW()).

I made two test cases of mine, the first is ansi_string() which seem to work fine, the second is unicode_string() - which I don't quite understand how should I concat the additional "*" char to the unicoded path. I write the strings to a file, because I'm not able to print Unicoded characters to stdout.

Note: my goal is to learn, which means I'll appreciate guidance and references to the appropriate resources regards my scenario, I'm very much a beginner and this is my first attempt with Unicode.

Thanks, Doori Bar

#include <stdio.h>
#include <stdlib.h>
#include <wchar.h>
#include <string.h>
#include <errno.h>

void *error_malloc(int size);

void ansi_string(char **str1, char **str2);

void unicode_string(wchar_t **wstr1, wchar_t **wstr2);

void unicode_string(wchar_t **wstr1, wchar_t **wstr2)
{
  /* assign wstr1 with the path: \\?\c:\Français\ */
  *wstr1 = error_malloc((wcslen(L"\\\\?\\c:\\Français\\")+1) *sizeof(**wstr1));
  wcscpy(*wstr1,L"\\\\?\\c:\\Français\\");

  /* concat wstr1+"*" , assign wstr2 with: \\?\c:\Français\* */
  *wstr2 = error_malloc((wcslen(*wstr1) + 1 + 1) * sizeof(**wstr1));
  /* swprintf(*wstr2,"%ls*",*wstr1); */
  /* how should I concat wstr1+"*"? */
   wcscpy(*wstr2,L"\\\\?\\c:\\Français\\");
}

void ansi_string(char **str1, char **str2)
{
  /* assign str1 with the path: c:\English\ */
  *str1 = error_malloc(strlen("c:\\English\\") + 1);
  strcpy(*str1,"c:\\English\\");

  /* concat str1+"*" , assign str2 with: c:\English\* */
  *str2 = error_malloc(strlen(*str1) + 1 + 1);
  sprintf(*str2,"%s*",*str1);
}

void *error_malloc(int size)
{
  void *ptr;
  int errornumber;
  if ((ptr = malloc(size)) == NULL) {
    errornumber = errno;
    fprintf(stderr,"Error: malloc(): %d; Error Message: %s;\n",
            errornumber,strerror(errornumber));
    exit(1);
  }
  return ptr;
}

int main(void)
{
  FILE *outfile;
  char *str1;
  char *str2;
  wchar_t *wstr1;
  wchar_t *wstr2;

  if ((outfile = fopen("out.bin","w")) == NULL) {
    printf("Error: fopen failed.");
    return 1;
  }

  ansi_string(&str1,&str2);
  fwrite(str2, sizeof(*str2), strlen(str2), outfile);
  printf("strlen: %d\n",strlen(str2));
  printf("sizeof: %d\n",sizeof(*str2));
  free(str1);
  free(str2);

  unicode_string(&wstr1,&wstr2);
  fwrite(wstr2, sizeof(*wstr2), wcslen(wstr2), outfile);
  printf("wcslen: %d\n",wcslen(wstr2));
  printf("sizeof: %d\n",sizeof(*wstr2));
  free(wstr1);
  free(wstr2);

  fclose(outfile);
  return 0;
}

What's wrong with:

wchar_t *wcscat(wchar_t *dest, const wchar_t *src);

?

That should do the trick right?

I would include "tchar.h" and use the unicode equivalents of the standard C library.

strcat("my\path\", "*");

becomes.

_tcscat(_T("my\path\"),_T("*"));

FYI: You can use the standard version of the function call without the 'W' on the end. The compiler will map the regular call to the correct version depending on the unicode settings of you app. Assuming it's either all Unicode or not.

Based on your commented code you are trying to use swprintf so I will answer based on that.

In sprintf you can use %S for wide string parameters and %s for multi byte string parameters.

In swprintf you can use %s for wide string parameters and %S for multi byte character string parameters.

It's easy to remember if you just think that %s matches strings of the same type for the function you're using.

Example:

wchar_t wsz[1024];
char sz[1024];  
swprintf(wsz, L"%s %S", L"Hello", "world!");
sprintf(sz, "%S %s", L"Hello", "world!");