Portability Library Routines

The following tables list library routines for portability.

If you have programs that use these routines, it is recommended that they access the portability library with USE IFPORT.

Some routines in this library can be called with different sets of arguments, and some can be used as a function or a subroutine. In these cases, the arguments and calling mechanism determine the meaning of the routine. The IFPORT module contains generic interface blocks that give procedure definitions for these routines.

Fortran 2003 contains intrinsic procedures for many of the portability functions. The portability routines are extensions to the Fortran 2003 standard. When writing new code, use Fortran 2003 intrinsic procedures whenever possible (for portability and performance reasons).

Information Retrieval
Name	Procedure Type	Description
FOR_IFCORE_VERSION	Function	Returns the version of the Fortran run-time library (ifcore).
FOR_IFPORT_VERSION	Function	Returns the version of the Fortran portability library (ifport).
FSTAT	Function	Returns information about a logical file unit.
GETCWD	Function	Returns the pathname of the current working directory.
GETENV	Subroutine	Searches the environment for a given string and returns its value if found.
GETGID	Function	Returns the group ID of the user.
GETLOG	Subroutine	Returns the user's login name.
GETPID	Function	Returns the process ID of the process.
GETUID	Function	Returns the user ID of the user of the process.
HOSTNAM ^¹	Function	Returns the name of the user's host.
ISATTY	Function	Checks whether a logical unit number is a terminal.
LSTAT	Function	Returns information about a named file. STAT is the preferred form of this function.
RENAME	Function	Renames a file.
STAT	Function	Returns information about a named file.
UNLINK	Function	Deletes the file given by path.

Process Control
Name	Procedure Type	Description
ABORT	Subroutine	Stops execution of the current process, clears I/O buffers, and writes a string to external unit 0.
ALARM	Function	Executes an external subroutine after waiting a specified number of seconds.
KILL	Function	Sends a signal code to the process given by ID.
SIGNAL	Function	Changes the action for signal.
SLEEP	Subroutine	Suspends program execution for a specified number of seconds.
SYSTEM	Function	Executes a command in a separate shell.

Numeric Values and Conversion
Name	Procedure Type	Description
BESJ0, BESJ1, BESJN, BESY0, BESY1, BESYN	Functions	Return single-precision values of Bessel functions of the first and second kind of orders 1, 2, and n, respectively.
BIC, BIS	Subroutines	Perform bit level clear, set, and test for integers.
BIT	Function	Performs bit level clear, set, and test for integers.
CDFLOAT	Function	Converts a COMPLEX(4) argument to DOUBLE PRECISION type.
COMPLINT, COMPLREAL, COMPLLOG	Functions	Return a BIT-WISE complement or logical .NOT. of the argument.
CSMG	Function	Performs an effective BIT-WISE store under mask.
DBESJ0, DBESJ1, DBESJN, DBESY0, DBESY1, DBESYN	Functions	Return double-precision values of Bessel functions of the first and second kind of orders 1, 2, and n, respectively.
DFLOATI, DFLOATJ, DFLOATK	Functions	Convert an integer to double-precision real type.
DRAND, DRANDM	Functions	Return random numbers between 0.0 and 1.0.
DRANSET	Subroutine	Sets the seed for the random number generator.
IDFLOAT	Function	Converts an INTEGER(4) argument to double-precision real type.
IFLOATI, IFLOATJ	Functions	Convert an integer to single-precision real type.
INMAX	Function	Returns the maximum positive value for an integer.
INTC	Function	Converts an INTEGER(4) argument to INTEGER(2) type.
IRAND, IRANDM	Functions	Return a positive integer in the range 0 through 231-1 or 215-1 if called without an argument.
IRANGET	Subroutine	Returns the current seed.
IRANSET	Subroutine	Sets the seed for the random number generator.
JABS	Function	Computes an absolute value.
LONG	Function	Converts an INTEGER(2) argument to INTEGER(4) type.
QRANSET	Subroutine	Sets the seed for a sequence of pseudo-random numbers.
RAND, RANDOM ^²	Functions	Return random values in the range 0 through 1.0.
RANF	Function	Generates a random number between 0.0 and RAND_MAX.
RANGET	Subroutine	Returns the current seed.
RANSET	Subroutine	Sets the seed for the random number generator.
SEED	Subroutine	Changes the starting point of RANDOM.
SHORT	Function	Converts an INTEGER(4) argument to INTEGER(2) type.
SRAND	Subroutine	Seeds the random number generator used with IRAND and RAND.

Input and Output
Name	Procedure Type	Description
ACCESS	Function	Checks a file for accessibility according to mode.
CHMOD	Function	Changes file attributes.
FGETC	Function	Reads a character from an external unit.
FLUSH	Function	Flushes the buffer for an external unit to its associated file.
FPUTC	Function	Writes a character to an external unit.
FSEEK	Subroutine	Repositions a file on an external unit.
FTELL, FTELLI8	Function	Return the offset, in bytes, from the beginning of the file.
GETC	Function	Reads a character from unit 5.
GETPOS, GETPOSI8	Functions	Return the offset, in bytes, from the beginning of the file.
PUTC	Function	Writes a character to unit 6.

Date and Time
Name	Procedure Type	Description
CLOCK	Function	Returns current time in HH:MM:SS format using a 24-hour clock.
CLOCKX	Subroutine	Returns the processor clock to the nearest microsecond.
CTIME	Function	Converts system time to a 24-character ASCII string.
DATE ^³	Subroutine or Function	Returns the current system date.
DATE4	Subroutine	Returns the current system date.
DCLOCK	Function	Returns the elapsed time in seconds since the start of the current process.
DTIME	Function	Returns CPU time since later of (1) start of program, or (2) most recent call to DTIME.
ETIME	Function	Returns elapsed CPU time since the start of program execution.
FDATE	Subroutine or Function	Returns the current date and time as an ASCII string.
GETDAT	Subroutine	Returns the date.
GETTIM	Subroutine	Returns the time.
GMTIME	Subroutine	Returns Greenwich Mean Time as a 9-element integer array.
IDATE ^³	Subroutine	Returns the date either as one 3-element array or three scalar parameters (month, day, year).
IDATE4	Subroutine	Returns the date either as one 3-element array or three scalar parameters (month, day, year).
ITIME	Subroutine	Returns current time as a 3-element array (hour, minute, second).
JDATE ^³	Function	Returns current date as an 8-character string with the Julian date.
JDATE4	Function	Returns current date as a 10-character string with the Julian date.
LTIME	Subroutine	Returns local time as a 9-element integer array.
RTC	Function	Returns number of seconds since 00:00:00 GMT, Jan 1, 1970.
SECNDS	Function	Returns number of seconds since midnight, less the value of its argument.
SETDAT	Function	Sets the date.
SETTIM	Function	Sets the time.
TIME	Subroutine or Function	As a subroutine, returns time formatted as HH:MM:SS; as a function, returns time in seconds since 00:00:00 GMT, Jan 1, 1970.
TIMEF	Function	Returns the number of seconds since the first time this function was called (or zero).

Error Handling
Name	Procedure Type	Description
GETLASTERROR	Function	Returns the last error set.
GETLASTERRORQQ	Function	Returns the last error set by a run-time function or subroutine.
IERRNO	Function	Returns the last code error.
SETERRORMODEQQ	Subroutine	Sets the mode for handling critical errors.

Program Control
Name	Procedure Type	Description
RAISEQQ	Function	Sends an interrupt to the executing program, simulating an interrupt from the operating system.
RUNQQ	Function	Calls another program and waits for it to execute.
SIGNALQQ	Function	Controls signal handling.
SLEEPQQ	Subroutine	Delays execution of the program for the specified time.

System, Drive, and Directory
Name	Procedure Type	Description
CHDIR	Function	Changes the current working directory.
CHANGEDIRQQ	Function	Makes the specified directory the current (default) directory.
CHANGEDRIVEQQ	Function	Makes the specified drive the current drive.
DELDIRQQ	Function	Deletes a specified directory.
GETDRIVEDIRQQ	Function	Returns the current drive and directory path.
GETDRIVESIZEQQ	Function	Gets the size of the specified drive.
GETDRIVESQQ	Function	Reports the drives available to the system.
GETENVQQ	Function	Gets a value from the current environment.
MAKEDIRQQ	Function	Makes a directory with the specified directory name.
SETENVQQ	Function	Adds a new environment variable, or sets the value of an existing one.
SYSTEMQQ	Function	Executes a command by passing a command string to the operating system's command interpretor.

Speaker
Name	Procedure Type	Description
BEEPQQ	Subroutine	Sounds the speaker for a specified duration in milliseconds at a specified frequency in Hertz.

File Management
Name	Procedure Type	Description
DELFILESQQ	Function	Deletes the specified files in a specified directory.
FINDFILEQQ	Function	Searches for a file in the directories specified in the PATH environment variable.
FULLPATHQQ	Function	Returns the full path for a specified file or directory.
GETFILEINFOQQ	Function	Returns information about files with names that match a request string.
PACKTIMEQQ	Subroutine	Packs time values for use by SETFILETIMEQQ.
RENAMEFILEQQ	Function	Renames a file.
SETFILEACCESSQQ	Function	Sets file-access mode for the specified file.
SETFILETIMEQQ	Function	Sets modification time for a given file.
SPLITPATHQQ	Function	Breaks a full path into four components.
UNPACKTIMEQQ	Subroutine	Unpacks a file's packed time and date value into its component parts.

Arrays
Name	Procedure Type	Description
BSEARCHQQ	Function	Performs a binary search for a specified element on a sorted one-dimensional array of non-structure data types (derived types are not allowed).
SORTQQ	Subroutine	Sorts a one-dimensional array of non-structure data types (derived types are not allowed).

Floating-Point Inquiry and Control
Name	Procedure Type	Description
CLEARSTATUSFPQQ	Subroutine	Clears the exception flags in the floating-point processor status word.
GETCONTROLFPQQ	Subroutine	Returns the value of the floating-point processor control word.
GETSTATUSFPQQ	Subroutine	Returns the value of the floating-point processor status word.
LCWRQQ	Subroutine	Same as SETCONTROLFPQQ.
SCWRQQ	Subroutine	Same as GETCONTROLFPQQ.
SETCONTROLFPQQ	Subroutine	Sets the value of the floating-point processor control word.
SSWRQQ	Subroutine	Same as GETSTATUSFPQQ.

IEEE Functionality
Name	Procedure Type	Description
IEEE_FLAGS	Function	Sets, gets, or clears IEEE flags.
IEEE_HANDLER	Function	Establishes a handler for IEEE exceptions.

Serial Port I/O^⁴
Name	Procedure Type	Description
SPORT_CANCEL_IO	Function	Cancels any I/O in progress to the specified port.
SPORT_CONNECT	Function	Establishes the connection to a serial port and defines certain usage parameters.
SPORT_CONNECT_EX	Function	Establishes the connection to a serial port, defines certain usage parameters, and defines the size of the internal buffer for data reception.
SPORT_GET_HANDLE	Function	Returns the Windows* handle associated with the communications port.
SPORT_GET_STATE	Function	Returns the baud rate, parity, data bits, and stop bit settings of the communications port.
SPORT_GET_STATE_EX	Function	Returns the baud rate, parity, data bits setting, stop bits, and other settings of the communications port.
SPORT_GET_TIMEOUTS	Function	Returns the user selectable timeouts for the serial port.
SPORT_PEEK_DATA	Function	Returns information about the availability of input data.
SPORT_PEEK_LINE	Function	Returns information about the availability of input records.
SPORT_PURGE	Function	Executes a purge function on the specified port.
SPORT_READ_DATA	Function	Reads available data from the port specified.
SPORT_READ_LINE	Function	Reads a record from the port specified.
SPORT_RELEASE	Function	Releases a serial port that has previously been connected.
SPORT_SET_STATE	Function	Sets the baud rate, parity, data bits and stop bit settings of the communications port.
SPORT_SET_STATE_EX	Function	Sets the baud rate, parity, data bits setting, stop bits, and other settings of the communications port.
SPORT_SET_TIMEOUTS	Function	Sets the user selectable timeouts for the serial port.
SPORT_SHOW_STATE	Function	Displays the state of a port.
SPORT_SPECIAL_FUNC	Function	Executes a communications function on a specified port.
SPORT_WRITE_DATA	Function	Outputs data to a specified port.
SPORT_WRITE_LINE	Function	Outputs data to a specified port and follows it with a record terminator.

**Miscellaneous**
Name	Procedure Type	Description
LNBLNK	Function	Returns the index of the last non-blank character in a string.
QSORT	Subroutine	Returns a sorted version of a one-dimensional array of a specified number of elements of a named size.
RINDEX	Function	Returns the index of the last occurrence of a substring in a string.
SCANENV	Subroutine	Scans the environment for the value of an environment variable.
TTYNAM	Subroutine	Checks whether a logical unit is a terminal.

¹ This routine can also be specified as HOSTNM.

² There is also a RANDOM subroutine in the portability library.

³ The two-digit year return value of DATE, IDATE, and JDATE may cause problems with the year 2000. Use the intrinsic subroutine DATE_AND_TIME instead.

⁴ W*S