For non-ASA variable text files, the default for z/OS® XL C/C++ is to ignore any empty physical records in the file. If a physical record contains a single blank, z/OS XL C/C++ reads in a logical record containing only a new-line. However, if the environment variable _EDC_ZERO_RECLEN was set to Y, z/OS XL C/C++ reads an empty physical record as a logical record containing a new-line, and a physical record containing a single blank as a logical record containing a blank and a new-line. z/OS XL C/C++ differentiates between empty records and records containing single blanks, and does not ignore either of them. For more information about how z/OS XL C/C++ treats empty records in variable format, see Mapping C types to variable format.
For ASA variable text files, if a file was created without a control character as its first byte, the first byte defaults to the ' ' character. When the file is read back, the first character is read as a new-line.
On input, ASA characters are translated to the corresponding sequence of control characters. For more information about using ASA files, refer to Using ASA text files.
For undefined format text files, reading a file causes a new-line character to be inserted at the end of each record. On input, a record containing a single blank character is considered an empty record and is translated to a new-line character. Trailing blanks are preserved for each record.
For files opened in fixed text format, rightmost blanks are stripped off a record at input, and a new-line character is placed in the logical record. This means that a record consisting of a single new-line character is represented by a fixed-length record made entirely of blanks.