HP 3000 Manuals HP 3000 Manuals
Reading a File in Sequential Order SPL uses the FREAD intrinsic to read all or part of a record in a sequential file with fixed- or variable-length records. A logical record pointer points to the next record to be read. When any part of a record is read, the pointer advances to the next record. HP C/XL has several ways to read records. The fgets function is probably the closest to the SPL action: a requested number of bytes or all the characters up to the end of the record are read into a buffer. If the end of record was reached, HP C/XL marks it by appending a '\n' (linefeed) character to the record data in the buffer. In any case, HP C/XL appends a '\0' (NUL) character to mark the end of the data in the buffer. Alternatively, the HP C/XL fread function can be used to read fixed-length binary data into a structure, such as an array or struct. Since fread does not recognize file record boundaries, you need to be sure the sizes you supply add up correctly. The conventional means of performing I/O in HP C/XL is to view data files as a "stream" of text (ASCII characters) in variable-length records. The functions contained in the HP C/XL library provide a rich set of formatted I/O operations, greatly simplifying the multiple steps which are necessary in SPL. Consideration of fixed-length record operations is required only to read files created in this manner by other programs, or to create files for programs that expect to read fixed-length records.