FSCANF(1)                   C LIBRARY FUNCTIONS                    FSCANF(1)

NAME
     fscanf, scanf, sscanf - formatted input functions.

SYNOPSIS
     int fscanf(const char *cntrl_string, ...);

     int scanf(FILE *fp, const char *cntrl_string, ...);

     int sscanf(char *s, const char *cntrl_string, ...);

INCLUDE FILE
     stdio.h
 
DESCRIPTION
     fscanf() reads text from the file associated with fp, converts the
          characters according to the conversion specification in
          cntrl_string, placing the values in memory at the addresses
          specified by the other arguments. fscanf() returns the number of
          conversion accomplished, or EOF if an end-of-file is encountered
          or if no conversion have occurred.


writes all its arguments into the file related to fp, in a
          format described by cntrl_string. Each argument to print is
          represented by a template starting with a % end ending with a
          conversion character. The number of argument to print must match
          the number of templates in the format string. Extra argument will
          be ignored, but to few argument will produce unpredictable
          results.
          fprintf returns the number of character written, or a negative
          number if an error occurs.

     scanf() is equivalent to fscanf(stdin, , ...).

     sscanf() is equivalent to scanf(), except that it reads from the string
          s instead of a file.

     Each of these functions convert formats, and read their arguments
     under control of the format string. The format is a character string
     which contains blanks or tabs which are ignored, Ordinary character
     (excluding %) which are expected to match the next non blank character
     of the input stream, and conversion specifications, each of which causes
     conversion of a string into variable pointed to by the corresponding
     argument.

     Each conversion specification is of the form

          %*n(l|L|h)t

     where all the parameters are optional apart from the type t.

     - * : if present, it means that the conversion should be performed, but
           but the result should not be stored. Their should be no argument
           pointer for that conversion.

     - n : an integer that specifies the maximal scan width.

     - l/L/h : indicates that the pointer refers to a long or short type of
             object. For integers object (d,i,o,u,x,X), l means that the
             object must be stored in a long integer. For float objects
             (e,E,g,G,f), it means that the object must be stored in a
             double. L can precede e,E,g,G or f to indicated that the
             converted value must be stored in a long double.

     - t : c   : any char, converted to (arg: char *).
           d,i : optionally signed decimal integer (arg: int *).
           u   : optionally signed decimal integer (arg: unsigned int *).
           o   : optionally signed octal integer (arg: unsigned int *).
           x,X : optionally signed hexadecimal integer (arg: unsigned int *).
           s   : a sequence of non white space characters. (arg: char *).
                  A string ends with a BLANK SPACE or '\n'.
   - f,e,E,g,G : optionally signed floating point number. (arg :float *).
           p   : what is produced by %p in printf() (usually an unsigned
                  hexadecimal number)                 (arg : void * *).
           n   : the corresponding argument is a pointer to an integer
                  into which the number of character read so far is put.
           %   : %% prints the '%' sign.
         [...] : Matches the longest non-empty string of input character
                  that only contains characters listed inside the brackets.
                  (arg : char *).
         [^..] : Matches the longest non-empty string of input character
                  that contains any characters but those listed inside the
                  brackets. (arg : char *).
EXAMPLES
   - if a file containing

          4 5 , Disregard_this, x This_is_a_string

     is read by the following call to fscanf(),

      int i;
      short j;
      char *str,Buff[125];
      FILE *fp;

      /* open the file */

      fscanf(fp,"%d %hd , %*s %% %c %4s %s ",&i,&j,str,Buff);

   then, the variable will contain the following:

      i => 4, j => 5, str => This, Buff => _is_a_string .

   - If the following program

     main()
     { char mantissa[20],exponent[20];

       scanf("%[^Ee]%[1234567890]",mantissa,exponent);
       printf("%se%s\n",mantissa,exponent);

     }

     is given 123e4 in input, it will print 123E4 on the stdout.

SEE ALSO
   open(), close(), getc(), printf().