Pf out

18.4.0 released Sep 25, 2023

Pf out

Purpose: Outputs a formatted string without encoding.

pf-out [ format ] <format> <expression> [ , <expression> ]... \
    [ bytes-written [ define ] <bytes> ] \
    [ to-error ] \
    [ to [ define ] <string> ]

pf-out formats a string according to the <format> string and a list of variable-type <expression>s (in the same way C's "printf()" does) and then outputs the result without any encoding (meaning a string is output exactly as it is, and the client may interpret such text in any way it sees fit). The result is sent to a client that made the request. If another string is built by using write-string, then the result is output into the buffer that builds a new string.

<format> string must be present. If you'd like to know the number of bytes written out, use the optional "bytes-written" clause, in which case <bytes> holds the number of bytes written; use "define" clause to create it within the statement. There must be at least one <expression> (it means if you want to print out a simple string literal you still have to use "%s" as format).

If <format> is a string constant (eg. "%s %d"), you can omit "format" clause in front of it; however if it is not a string constant (eg. a variable), then you must use "format" clause in front of <format>.

If the optional "to-error" clause is used, the output is sent to "stderr", or standard output stream.

If the optional "to" clause is used, then the output of pf-out is stored into <string>. The <string> can be created with optional "define". <string> is allocated memory.

Examples

To output data (the string output is "the number is 20" and the number of bytes written is in variable "bwritten"):

pf-out bytes-written define bwritten "%s is %d", "the number", 20

The following is writing to client, outputting text for which the browser will interpret tags "<br/>" and "<hr/>" as a line break and a horizontal line and display them as such. It also demonstrates use of "format" clause when <format> is not a constant:

char *fmt = "<hr/> %s <br/>";
pf-out format fmt, "This is a non-encoded output"

Create a query text string by means of write-string statement:

void get_table_data (const char *table_name, num id_num)
{

   //
   // Construct the run-time text of dynamic SQL
   //
   write-string define qry_txt
   @select * from <<pf-out "%s where id="%lld", table_name, id_num>>
   end-write-string
 
}