| abort | terminate abruptly with memory image |
| access | determine accessibility of a file |
| alarm | execute a subroutine after a specified time |
| bessel functions, bessel | of two kinds for integer orders |
| bit | and, or, xor, not, rshift, lshift, bic, bis, bit, setbit functions |
| chdir | change default directory |
| chmod | change mode of a file |
| dtime, etime | return elapsed execution time |
| exit | terminate process with status |
| f77_floatingpoint | Fortran IEEE floating-point definitions |
| IEEE environment, f77_ieee_environment | mode, status, and signal handling subprograms for IEEE arithmetic |
| fdate | return date and time in an ASCII string |
| flush | flush output to a logical unit |
| fork | create a copy of this process |
| intro, fortran | introduction to FORTRAN library functions |
| free | deallocate a region of memory previously allocated by malloc |
| ftell, fseek | reposition a file on a logical unit |
| iargc, getarg | return command line arguments |
| fgetc, getc | get a character from a logical unit |
| getcwd | get pathname of current working directory |
| getenv | get value of environment variables |
| getfd | get the file descriptor of an external unit number |
| getlog | get user’s login name |
| getpid | get process id |
| getgid, getuid | get user or group ID of the caller |
| hostnm | get name of current host |
| itime, idate | return date or time in numerical form |
| rindex, lnblnk, len, index | tell about character strings |
| intro | introduction to FORTRAN library functions |
| ioinit | change f77 I/O initialization |
| kill | send a signal to a process |
| len | return the declared length of a character string |
| libm_double | Double-precision Fortran access to libm functions |
| libm_single | Single-precision Fortran access to libm functions |
| symlnk, link | make a link to an existing file |
| loc | return the address of an object |
| short, long | integer object conversion |
| malloc | allocate an amount of memory and return the address |
| gerror, ierrno, perror | get system error messages |
| fputc, putc | write a character to a FORTRAN logical unit |
| qsort | quick sort |
| drand, irand, rand | return random values |
| inmax, range | return maximum positive integer |
| rename | rename a file |
| signal | change the action for a signal |
| sleep | suspend execution for an interval |
| lstat, fstat, stat | get file status |
| system | execute a UNIX command |
| ctime, ltime, gmtime, time | return system time |
| tclose, tread, twrite, trewin, tskipf, tstate, topen | f77 tape I/O |
| isatty, ttynam | find name of a terminal port |
| unlink | remove a directory entry |
| wait | wait for a process to terminate |