A file pointer to a previously opened file. This may be either a file in the file system, or a string opened for read and write.
This function flushes any pending output on the file or string. This has the effect of printing output on the screen or updating a file on disk in the case of a file. flush has no effect on strings. flush is called automatically by close.
Gamma> fp=open("myflushfile.dat","w",nil);
#<File:"myflushfile.dat">
Gamma> write(fp, "I am written.");
t
Gamma> fp=open("myflushfile.dat","r",nil);
#<File:"myflushfile.dat">
Gamma> read_line(fp);
"Unexpected end of file"
Gamma> fp=open("myflushfile.dat","w",nil);
#<File:"myflushfile.dat">
Gamma> write(fp, "I am written.");
t
Gamma> flush(fp);
t
Gamma> fp=open("myflushfile.dat","r",nil);
#<File:"myflushfile.dat">
Gamma> read_line(fp);
"\"I am written.\""
Gamma>