.TH FORK 3F .UC .SH NAME fork \- create a copy of this process .SH SYNOPSIS .B integer function fork() .SH DESCRIPTION .I Fork creates a copy of the calling process. The only distinction between the 2 processes is that the value returned to one of them (referred to as the 'parent' process) will be the process id if the copy. The copy is usually referred to as the 'child' process. The value returned to the 'child' process will be zero. .PP All logical units open for writing are flushed before the fork to avoid duplication of the contents of I/O buffers in the external file(s). .PP If the returned value is negative, it indicates an error and will be the negation of the system error code. See perror(3F). .PP A corresponding .I exec routine has not been provided because there is no satisfactory way to retain open logical units across the exec. However, the usual function of .I fork/exec can be performed using system(3F). A pipe can be opened to another process using the f77 .B open statement with .sp 1 .ti +5 .B "file=\(fm\fIprocess\fB\(fm, status=\(fmpipe\(fm, access=\(fmread\(fm" .br or .br .ti +5 .B "file=\(fm\fIprocess\fB\(fm, status=\(fmpipe\(fm, access=\(fmwrite\(fm" .SH FILES /usr/lib/libU77.a .SH "SEE ALSO" fork(2), kill(3F), perror(3F), system(3F), wait(3F)