36. fgets

Synopsis

Read a line from a file.

Usage

Integer_Type fgets (SLang_Ref_Type ref, File_Type fp)

Description

fgets reads a line from the open file specified by fp and places the characters in the variable whose reference is specified by ref. It returns -1 if fp is not associated with an open file or an attempt was made to read at the end the file; otherwise, it returns the number of characters read.

Example

The following example returns the lines of a file via a linked list:

    define read_file (file)
    {
       variable buf, fp, root, tail;
       variable list_type = struct { text, next };

       root = NULL;

       fp = fopen(file, "r");
       if (fp == NULL)
         error("fopen %s failed." file);
       while (-1 != fgets (&buf, fp))
         {
            if (root == NULL)
              {
                 root = @list_type;
                 tail = root;
              }
            else
              {
                 tail.next = @list_type;
                 tail = tail.next;
              }
            tail.text = buf;
            tail.next = NULL;
         }
       () = fclose (fp);
       return root;
    }

See Also

fopen, fclose, fputs, error