"miwei" <miwei@xxxxxxxxx> writes: > I fine there are many #line xxx c-parse.y statements in c-parse.c file. > What is the use of the #line pragma? When I gdb the yyparse function, > I find it is not line-by-line consistent with the c-parse.c file. How to > make > the gdb process easier? Thanks #line is a standard C preprocessing directive. From ISO C 99 6.10.4: A preprocessing directive of the form # line digit-sequence new-line causes the implementation to behave as if the following sequence of source lines begins with a source line that has a line number as specified by the digit sequence (interpreted as a decimal integer). The digit sequence shall not specify zero, nor a number greater than 2147483647. A preprocessing directive of the form # line digit-sequence "s-char-sequenceopt" new-line sets the presumed line number similarly and changes the presumed name of the source file to be the contents of the character string literal. This will affect the debugging information, which is read by gdb. Ian