C in a Nutshell

Name

wcsstr

Synopsis

Searches a wide string for a replica of another wide string

#include <wchar.h>
wchar_t *wcsstr( const wchar_t *s1, const wchar_t *s2 );

The wcsstr() function searches the wide string addressed by s1 for the sequence of wide characters contained in s2, not counting the terminating null wide character. The return value is a pointer to the first wide character in the first occurrence in s1 of the sequence contained in s2, or a null pointer if there is no such occurrence. If s2 points to an empty wide string, then wcsstr() returns the value of its first argument, s1.

Example

This simple program prints each line in a file that contains a given keyword:

#define MAX_LINE 1024

int main( int argc, char **argv )
{
  FILE *fpIn = NULL;
  wchar_t keyword[MAX_LINE] = { L'\0' };
  wchar_t line[MAX_LINE] = { L'\0' };

  if ( argc != 3 )
  {
    wprintf( L"Syntax: %s <keyword> <filename>\n", argv[0] );
    return -1;
  }

  if (( fpIn = fopen( argv[2], "r" )) == NULL )
    return -2;
  else
    fwide( fpIn, 1 );

  if ( mbstowcs( keyword, argv[1], MAX_LINE ) == -1 )
    return -3;

  int count = 0;
  while ( fgetws( line, MAX_LINE, fpIn ) != NULL )
    if (wcsstr( line, keyword ) != NULL )
      {
        ++count;
        fputws( line, stdout );
      }

  if ( !feof( fpIn ))
    return -4;
  else
    return count;
}

See Also

wcspbrk(), wcsspn(), wcscspn(), wcschr(), wcsrchr(), strstr(), strpbrk(), strspn(), strcspn(), strchr(), strrchr()