HP C A.06.05 Reference Manual

Preprocessing Directives
Line Control (#line)
Chapter 7198
Line Control (#line)
You can cause the compiler to increment line numbers during compilation from a number
specified in a line control directive. (The resulting line numbers appear in error message
references, but do not alter the line numbers of the actual source code.)
Syntax
line-directive ::=
#line digit-sequence [filename]
Description
The #line preprocessing directive causes the compiler to treat lines following it in the
program as if the name of the source file were filename and the current line number is
digit-sequence. This is to control the file name and line number that is given in diagnostic
messages, for example. This feature is used primarily for preprocessor programs that
generate C code. It enables them to force the HP C compiler to produce diagnostic messages
with respect to the source code that is input to the preprocessor rather than the C source code
that is output and subsequently input to the compiler.
HP C defines two macros that you can use for error diagnostics. The first is __LINE__, an
integer constant equal to the value of the current line number. The second is __FILE__, a
quoted string literal equal to the name of the input source file. Note that you can change
__FILE__ and __LINE__ using #include or #line directives.
Example
#line digit-sequence [filename] : #line 5 "myfile"