GNU assembler: creating a symbol using macro argument -

i have macro creates labels, want create labels if aren't defined. problem label built using macro argument, , assembler doesn't symbols generated using macro arguments. code doesn't work. errors out on ifndef. there other way write this?

.macro create_handler modifier   .ifndef handler\modifier     handler\modifier:     code     more code   .endif .endif 

error: junk @ end of line, first unrecognized character `\'

i think there 2 problems. 1 \modifier: looks macro argument named modifier:, colon. need use \modifier\(): instead. \() breaks string parser knows have ended name of argument.

second, last .endif should .endm:

.macro create_handler modifier   .ifndef handler\modifier     handler\modifier\():       .4byte 0   .endif .endm  create_handler foo create_handler foo 

this results in listing (ignore line numbers, added 1 of existing files):

  74 0010 00000000  create_handler foo   75                create_handler foo defined symbols   ../src/core_dict.s:74     .text:00000010 handlerfoo 

as can see, 1 handlerfoo created.