Boilerplate (text):

Boilerplate is any text that is or can be reused in new contexts or applications without being changed much from the original. Many computer programmers often use the term boilerplate code. A legal boilerplate is a standard provision in a contract.

The term dates back to the early 1900s, referring to the thick, tough steel sheets used to build steam boilers. From the 1890s onwards, printing plates of text for widespread reproduction such as advertisements or syndicated columns were cast or stamped in steel (instead of the much softer and less durable lead alloys used otherwise) ready for the printing press and distributed to newspapers around the United States. They came to be known as 'boilerplates'. Until the 1950s, thousands of newspapers received and used this kind of boilerplate from the nation's largest supplier, the Western Newspaper Union.

Some companies also sent out press releases as boilerplate so that they had to be printed as written. The modern equivalent is the press release boilerplate, or "boiler," a paragraph or two that describes the company and its products.

The word has also come into use for pre-created form letters on the Internet for things such as issues to be broached by a politician based on an issue ad, requesting a cable network be added to a system by a cable or satellite operator, or a pre-written complaint about something such as a program, book, or video game opposed by a group which created the letter, along with online petitions. Usually the greeting and the body of the letter have been pre-written, requiring the person requesting the action to only type or sign their name at the end.

Boilerplate language

The term boilerplate is adopted by lawyers to describe those parts of a contract that are considered "standard language", although it is good practice to always read the boilerplates in any contract.

Boilerplate code

In computer programming, boilerplate is the term used to describe sections of code that have to be included in many places with little or no alteration. It is more often used when referring to languages which are considered verbose, i.e. the programmer must write a lot of code to do minimal jobs. The need for boilerplate can be reduced through high-level mechanisms such as Metaprogramming (which has the computer automatically write the needed boilerplate text) and Convention over Configuration (which provides good defaults values, reducing the need to specify program details in every project).

The following Perl example demonstrates boilerplate. It consists of a shebang and two pragmas mandated by good programming style at the beginning of a source file. These lines aren't part of the program logic but convey information for the execution environment.

#!/usr/bin/perl
use warnings;
use strict;

A frequent source of boilerplate comes from the need to prepare the use of a general library having a low level of abstraction. An example is the strcat function in C to append two strings. Since there is no String type in the C language, strings are represented as an array of characters that ends with the NULL value. The code needed to call strcat to create a new string by appending two strings called first and second would be:

char *result;
 
/* Allocate memory for the size of the two strings, plus 1 for the terminating NULL character. */
result = malloc(strlen(first) + strlen(second) + 1);
 
/* Copy the contents of 'first' to 'result'. */
strcpy(result, first);
 
/* Append the contents of 'second'. */
strcat(result, second);
 
...
 
/* Deallocate the reserved memory when finished */
free(result);

The variable declaration, malloc and free statements are the boilerplate needed to prepare for the actual work performed by the two function calls.

Boilerplate (text)

Boilerplate language

Boilerplate code

See also