Text file manipulation routines apply only to text files (including INPUT, OUTPUT, and ERR).
1 – EOLN
The EOLN function tests for the end-of-line marker within a text file and returns a Boolean value. Syntax: EOLN [[( file_variable )]] The 'file_variable' is the name of a file variable associated with a text file. If you omit the name of the file, the default is INPUT. The file must be in inspection mode and EOF must return FALSE before EOLN is called. EOLN leaves the file in inspection mode. The Boolean EOLN function returns TRUE when the file pointer is positioned after the last character in a line. When the EOLN function returns TRUE, the file buffer contains a blank character. The EOLN function returns FALSE when the last component in the line is read into the file buffer. Another character must be read to cause EOLN to return TRUE and to cause the file buffer to be positioned at the end-of-line marker following the last character of the line. If you use the EOLN function on a nontext file, an error occurs. See the "HP Pascal Language Reference Manual" for a complete description of the EOLN function.
2 – LINELIMIT
The LINELIMIT procedure stops execution of the program after a specified number of lines has been written into a TEXT file. Syntax: LINELIMIT( file_variable, n [[, ERROR := error-recovery]] ); The 'file_variable' is the name of the file variable associated with the TEXT file to which the limit applies. The 'n' is a positive integer expression that indicates the number of lines that can be written to the file before execution terminates. The 'error-recovery' specifies the action to be taken if an error occurs during execution of the routine. By default, after the first error, the error message is printed and execution is stopped. The file can be in any mode before LINELIMIT is called; the file mode does not change after LINELIMIT has been executed. VSI Pascal first uses environment-specific means to determine if there is a default line limit. If there is not environment-specific default, there is no default line limit. You can use a call to LINELIMIT to override the default. After the number of lines written into the file has reached the line limit, program execution terminates unless the WRITELN procedure that exceeded the line limit includes the ERROR := CONTINUE parameter. See the "HP Pascal Language Reference Manual" for a complete description of the LINELIMIT procedure.
3 – PAGE
The PAGE procedure skips from the current page to the next page of a TEXT file. Syntax: PAGE( file_variable [[, ERROR := error-recovery]] ); The 'file_variable' is the name of the file variable associated with a TEXT file. The 'error-recovery' specifies the action to be taken if an error occurs during execution of the routine. By default, after the first error, the error message is printed and execution is stopped. The file must be in generation mode before the PAGE procedure is called; the mode does not change as a result of the procedure's execution. Execution of the PAGE procedure clears the record buffer, if it contains data, by performing a WRITELN procedure, and then advances the output to a new page of the specified TEXT file. The next component written to the file begins on the first line of a new page. You can use this procedure only on TEXT files. If you specify a file of any other type, an error occurs. The value of the page eject component that is output to the file depends on the carriage control format for that file. When CARRIAGE or FORTRAN is enabled, the page eject record is equivalent to the carriage control character '1'. When LIST, NOCARRIAGE, or NONE is enabled, the page eject record is a single form feed character. See the "HP Pascal Language Reference Manual" for a complete description of the PAGE procedure.
4 – READLN
The READLN procedure reads lines of data from a TEXT file. Syntax: READLN [[( [[file_variable,]] {variable-identifier [[:radix-specifier]]},... [[, ERROR := error-recovery]]) ]]; The 'file_variable' is the name of the file variable associated with the TEXT file to be read. If you omit the name of the file, the default is INPUT. The 'variable-identifier' is the name of the variable into which a file component will be read; multiple identifiers are separated by commas. If you do not specify any variable name, READLN skips a line in the specified file. The 'radix-specifier' is one of the format values BIN, OCT, or HEX. These values, when used on a variable identifier, read the variable in binary, octal, or hexadecimal, respectively. You can use a radix specifier only when reading from a TEXT file. The 'error-recovery' specifies the action to be taken if an error occurs during execution of the routine. By default, after the first error, the error message is printed and execution is stopped. The file must be in inspection mode before READLN is called; it remains in that mode after the procedure's execution. The READLN procedure reads values from a TEXT file. After reading values for all the listed variables, the READLN procedure skips over any characters remaining on the current line and positions the file at the beginning of the next line. The values need not all be on a single line; READLN continues until values have been assigned to all the specified variables, even if this process results in the reading of several lines of the input file. EOLN returns TRUE after a READLN procedure only if the new line is empty. See the "HP Pascal Language Reference Manual" for a complete description of the READLN procedure.
5 – WRITELN
The WRITELN procedure writes a line of data to a text file. Syntax: WRITELN [[( [[file_variable,]] {expression},... [[, ERROR := error-recovery]] )]] The 'file_variable' is the name of the file variable associated with the text file to be written. If you omit the name of the file, the default is OUTPUT. The 'expression' is an expression whose value is to be written; multiple output values must be separated by commas. The expressions can be of any ordinal, real, or string type and are written with a default field width. The 'error-recovery' specifies the action to be taken if an error occurs during execution of the routine. By default, after the first error, the error message is printed and execution is stopped. The file must be in generation mode before WRITELN is called; it remains in that mode after WRITELN has been executed. The WRITELN procedure writes the specified values into the TEXT file, inserts an end-of-line marker after the end of the current line, and then positions the file at the beginning of the next line. You can specify a carriage-control character as the first item in an output line. When you use carriage-control characters, make sure that the file is open with either the CARRIAGE or FORTRAN option. If you specify a carriage format but use an invalid carriage control character, the first character in the line is ignored. The output appears with the first character truncated. See the "HP Pascal Language Reference Manual" for a complete description of the WRITELN procedure.