File: gawk.info,  Node: Scalar Constants,  Next: Nondecimal-numbers,  Up: Constants

6.1.1.1 Numeric and String Constants
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A "numeric constant" stands for a number.  This number can be an
integer, a decimal fraction, or a number in scientific (exponential)
notation.(1)  Here are some examples of numeric constants that all have
the same value:

     105
     1.05e+2
     1050e-1

   A "string constant" consists of a sequence of characters enclosed in
double quotation marks.  For example:

     "parrot"

represents the string whose contents are 'parrot'.  Strings in 'gawk'
can be of any length, and they can contain any of the possible eight-bit
ASCII characters, including ASCII NUL (character code zero).  Other
'awk' implementations may have difficulty with some character codes.

   Some languages allow you to continue long strings across multiple
lines by ending the line with a backslash.  For example in C:

     #include 

     int main()
     {
         printf("hello, \
     world\n");
         return 0;
     }

In such a case, the C compiler removes both the backslash and the
newline, producing a string as if it had been typed '"hello, world\n"'.
This is useful when a single string needs to contain a large amount of
text.

   The POSIX standard says explicitly that newlines are not allowed
inside string constants.  And indeed, all 'awk' implementations report
an error if you try to do so.  For example:

     $ gawk 'BEGIN { print "hello,
     > world" }'
     -| gawk: cmd. line:1: BEGIN { print "hello,
     -| gawk: cmd. line:1:               ^ unterminated string
     -| gawk: cmd. line:1: BEGIN { print "hello,
     -| gawk: cmd. line:1:               ^ syntax error

   Although POSIX doesn't define what happens if you use an escaped
newline, as in the previous C example, all known versions of 'awk' allow
you to do so.  Unfortunately, what each one does with such a string
varies.  (d.c.)  'gawk', 'mawk', and the OpenSolaris POSIX 'awk' (*note
Other Versions::) elide the backslash and newline, as in C:

     $ gawk 'BEGIN { print "hello, \
     > world" }'
     -| hello, world

   In POSIX mode (*note Options::), 'gawk' does not allow escaped
newlines.  Otherwise, it behaves as just described.

   BWK 'awk' and BusyBox 'awk' remove the backslash but leave the
newline intact, as part of the string:

     $ nawk 'BEGIN { print "hello, \
     > world" }'
     -| hello,
     -| world

   ---------- Footnotes ----------

   (1) The internal representation of all numbers, including integers,
uses double-precision floating-point numbers.  On most modern systems,
these are in IEEE 754 standard format.  *Note Arbitrary Precision
Arithmetic::, for much more information.