spec

Software for Diffraction

printing

producing formatted output

DESCRIPTION

The print command and the printf() and fprintf() functions are used to send output to files or to the screen. In spec, files and devices are turned on or off using special commands (see the files help file), and printed output generally goes to all devices that are currently on. The fprintf() function differs in that it turns off output to everything except the file or device specified in its first argument.

The print command prints each of its arguments separated by spaces, and then prints a newline. Strings are printed as is, numbers are printed using the "%g" format.

The functions printf(), fprintf() and sprintf() use format specifications just like those in C. A few of those format specifications are %s to print a string, %g to print a floating point number and %d to print an integer. An embedded \n prints a newline. See the description of printf() in a C manual for more details.

BUILT-IN COMMANDS AND FUNCTIONS

print a, b ...
Prints each argument, separated by spaces.
printf(format, a, b ... )
Prints a, b, etc. using format.
fprintf(file_name, format [, a, ...])
Does formatted printing on file_name. All other devices (except log files) are turned off while the string is printed.
sprintf(format, a, b ... )
Returns a string holding the formatted print.

EXAMPLES

1.SPEC> print sqrt(2), PI, PRINTER
1.41412 3.14159 /dev/lp

2.SPEC> printf("Today is %s.  PI = %.3g\n",\
     date(), PI)
Today is Sat Jan 23 00:54:23 1988.  PI = 3.14



3.SPEC> FILENAME = sprintf("%s/data/run.%d",\
        HOME, run);

4.SPEC> print FILENAME
/usr/gerry/data/run.12

SEE ALSO

files

printf() in any C-language programming manual.